JP5119482B2 - Anti-dust fouling prevention device for electric dust collector - Google Patents

Description

  The present invention relates to a fouling prevention device for a soot tube provided around a high-voltage supply conducting wire that penetrates an electric dust collector main body structure.

  For example, in a coal combustion facility of a power plant, an electrostatic precipitator is used as a dust removing means for suppressing dust in exhaust gas discharged from the combustion facility below an environmental regulation value. Inside the electric dust collector, there are provided a discharge electrode for discharging to charge the dust to a negative charge and a dust collecting electrode for collecting the charged dust. The discharge electrode is electrically connected to a suspension tube that suspends the discharge electrode, which is provided through the structure portion of the electrostatic precipitator body. The suspension tube is insulated from the structure portion of the electrostatic precipitator body. In order to ensure, it is supported by the electric dust collector main body structure part through the cylindrical or conical soot pipe which consists of the insulator installed in the upper surface of the electric dust collector. And the high voltage supply conducting wire electrically connected to the high voltage power source for supplying a high voltage current to the discharge electrode is electrically connected to the suspension tube in the vicinity of the upper portion of the soot tube.

  In such an electrostatic precipitator, when dust adheres to the inner surface of the soot tube, that is, the surface in contact with the exhaust gas, a spark discharge is generated from the high-voltage supply lead due to dielectric breakdown of the soot tube. When spark discharge occurs, the discharge from the discharge electrode becomes unstable, and the dust cannot be collected by the electric dust collector. In the worst case, it is necessary to stop the coal combustion facility. Moreover, there is a possibility that the soot tube may be damaged by the spark discharge. When the soot tube is damaged, it is necessary to stop the electric dust collector and coal combustion, which is an exhaust gas generation source upstream, for repair. Therefore, from the viewpoint of plant operation, the electric dust collector is required to be stably operated continuously. For that reason, it is extremely important to prevent dust from adhering to the inner surface of the soot pipe. Therefore, in order to prevent dust from adhering to the inner surface of the soot tube, a cylindrical protective cylinder is usually provided below the soot tube. However, even if a protective cylinder is provided, it is not possible to completely prevent dust from entering the inside of the soot tube and attaching dust to the inside surface of the soot tube. In addition, dust adheres to the protective cylinder itself, which reduces the insulation distance between the high-voltage supply lead and the protective cylinder, causing insulation breakdown between the high-voltage supply lead and the protective cylinder, resulting in spark discharge. To do.

  Therefore, as means for preventing dust from adhering to the inner surface of the soot tube and the inner surface of the protection tube, for example, disclosed in Patent Document 1, high-pressure air is supplied from the opening at the top of the soot tube to the inside of the soot tube and the protection tube. In addition, a method of sealing inside the protective cylinder is generally employed.

JP 2002-260466 A

  However, for example, when using an electrostatic precipitator to remove dust in by-product gas generated from blast furnaces and converters at steelworks, the component of by-product gas is mainly combustible gas, so a safety point of view to prevent ignition Therefore, it is necessary to avoid supplying air, that is, oxygen into the electric dust collector. In addition, the by-product gas contains toxic gas and cannot be allowed to leak outside. For this reason, an electric dust collector that handles such a by-product gas usually has a structure in which the space between the soot tube and the dust collecting chamber of the electric dust collector is completely sealed, and the means disclosed in Patent Document 1 can be used. There is a problem that you can not.

  Therefore, in the electrostatic precipitator that handles such by-product gas, there is no effective means for preventing dust from adhering to the inside of the soot tube and the protective cylinder, and in order to remove and remove the adhering dust, the electrostatic precipitator is regularly used. It is essential to stop the operation and clean the inside. However, there is a problem that this cleaning work involves stopping and starting up facilities including peripheral devices, and requires a lot of labor and time. Further, in order to prevent dust from adhering to the inside of the soot pipe, in the method of Patent Document 1, sealing is performed using an inert gas that does not ignite even if supplied into by-product gas instead of air. In this case, since the high-pressure inert gas is supplied to the hollow portion of the soot tube, the supply amount becomes enormous. Therefore, there are problems that the operating cost increases and the inert gas supply equipment becomes large.

  The present invention has been made in view of the above points, and prevents dust from adhering to the soot pipe and the protective cylinder without using a large inert gas supply facility, and does not require periodic internal cleaning of the electric dust collector. Another object of the present invention is to stably operate an electric dust collector for a long period of time.

In order to achieve the above object, the present invention provides an antifouling device for a soot tube disposed around a suspension tube that suspends a discharge electrode disposed in a main body structure portion of an electrostatic precipitator. A lid that is provided on the upper surface of the main body structure portion and seals the upper surface of the soot tube in an airtight manner; and a protection that is provided below the soot tube and on the lower surface of the main body structure portion and is arranged around the suspension tube. And a bottom surface of the soot tube is hermetically provided with an upper surface of the main body structure portion, and an opening for supplying an inert gas toward the periphery of the suspension tube is formed in the protection tube. The upper surface of the soot tube and the bottom surface of the soot tube are a first seal member provided between the soot tube and the lid, and a second seal provided between the main body structure portion and the soot tube. And a member supported by a support provided above the lid and It is characterized by being airtightly closed by pressing a plurality of elastic member provided in contact with the upper surface of the body.

  According to the present invention, since the inert gas header having an opening formed in the protective cylinder is provided, a gas seal layer that seals the inside of the soot tube is formed by the inert gas blown from the opening toward the center of the protective cylinder. can do. Therefore, it is possible to prevent dust from entering the inside of the soot tube by this gas seal layer, thereby preventing dust from adhering to the inside of the soot tube. Moreover, since the upper surface of the soot tube is airtightly closed, the inert gas does not flow out from the top of the soot tube. For this reason, the inert gas blown out from the opening forms a downward flow that flows downward inside the protective cylinder. For this reason, the inside of the protective cylinder can be simultaneously sealed by the downward flow, and the inert gas to be supplied can be suppressed to a minimum amount necessary for sealing the inside of the protective cylinder.

  An annular inert gas header that is provided on the outer peripheral surface of the protective cylinder and that faces the opening, and that supplies the inert gas to the opening, and supplies the inert gas to the inert gas header And an inert gas supply pipe. The inert gas supply pipe may be provided so as to supply the inert gas along a circumferential direction of the inert gas header.

  The opening may be provided in a slit shape over the entire circumference of the inner surface of the protective cylinder, and the inert gas header is predetermined with respect to the discharge direction of the inert gas from the inert gas supply pipe. You may have the rectification | straightening member provided by inclining this angle.

  A heating device may be provided on the outer periphery of the soot tube, and the inert gas may be nitrogen.

  According to the present invention, it is possible to prevent dust from adhering to the soot pipe and the protective cylinder without using a large inert gas supply facility, so that the electrostatic precipitator can be used for a long period of time without performing internal cleaning of the electrostatic precipitator. Stable operation is possible.

It is a longitudinal cross-sectional view which shows the outline of a structure of the electric dust collector which has the soot pipe fouling prevention apparatus concerning this Embodiment. It is a cross-sectional view which shows the outline of a structure of the electric dust collector which has the soot pipe fouling prevention apparatus concerning this Embodiment. It is explanatory drawing which shows the apparatus structure in an insulator room. It is a top view which shows the structure of a support body vicinity. It is a cross-sectional view of the inert gas header concerning this Embodiment. It is a cross-sectional view of an inert gas header according to another embodiment.

  Embodiments of the present invention will be described below. FIG. 1 is an explanatory diagram showing an outline of the configuration of an electric dust collector 1 having a soot tube fouling prevention device according to the present embodiment.

  The main body structure portion 2 of the electrostatic precipitator 1 is supported by a frame 3, and gas inlets 4 for introducing by-product gas containing dust generated from, for example, a converter (not shown) on both side surfaces of the main body structure portion 2. And the gas outlet 5 which discharges by-product gas after dust is removed by the electrostatic precipitator 1 is provided. And by-product gas is distribute | circulated in the main-body structure part 2 through this gas inlet 4 and the gas outlet 5. FIG. A plurality of dust collection chambers 6 for removing dust from the gas to be treated are provided in the main body structure portion 2, and a plurality of dust collection electrodes 7 are parallel to the gas flow direction in each dust collection chamber 6. It is suspended from the structure part 2. The dust collection electrode 7 is grounded by a ground wire (not shown), and a discharge electrode 8 is provided between the dust collection electrode 7 and the dust collection electrode 7 as shown in FIG. The electrostatic precipitator 1 in the present embodiment is a so-called wet electrostatic precipitator, and a spray nozzle (not shown) that injects water over the entire surface of the dust collecting electrode 7 is provided in the vicinity of the dust collecting electrode 7. Yes. A hopper 9 is provided at the lower part of the main body structure 2 to discharge the dust washed away from the dust collecting electrode 7 together with water by water sprayed from the spray nozzle.

  A power supply device (not shown) that supplies high-voltage direct current to the discharge electrode 8 through the high-voltage supply lead 10 is installed outside the electric dust collector 1. The high voltage supply conducting wire 10 extends to the inside of an insulator chamber 11 provided in the upper part of the main body structure portion 2.

  Inside the insulator chamber 11, a soot tube fouling prevention device 12 is provided. The soot tube fouling prevention device 12 includes a substantially conical cylindrical soot tube 13 that secures insulation between the main body structure portion 2 and the high-voltage supply conductor 10. And a protective cylinder 14 provided so as to penetrate the main body structure portion 2 below the soot tube 13.

  In the insulator chamber 11, in addition to the above-described insulator tube 13 and protective cylinder 14 constituting the insulator tube fouling prevention device 12, as shown in FIG. 3, a plurality of pieces provided on the upper surface of the main body structure portion 2 via a pedestal 20. A support insulator 21, a support 22 formed of a conductor and supported on the lower surface of the plurality of support insulators 21, and a suspension tube 23 formed of the same conductor and suspended from the lower surface of the support 22 are provided. It has been. The suspension tube 23 is introduced into the dust collection chamber 6 through the interior of the soot tube 13, the interior of the protective cylinder 14, and the opening of the lid 30 described later, and is electrically connected to the discharge electrode 8. 8 is suspended. The suspension tube 23 is a stainless steel tube, for example, in this embodiment in consideration of corrosion caused by water from the spray nozzle. However, the suspension tube 23 is used in an environment where there is no risk of corrosion, such as a dry electrostatic precipitator. For example, carbon steel may be used. Moreover, the suspension tube 23 does not need to be tubular, and may be, for example, a cylindrical conductor.

  The support 22 is electrically connected to the high-voltage supply lead 10 and the suspension tube 23 introduced into the insulator chamber 11, and thereby supplies the high-voltage direct current supplied from the power supply device to the discharge electrode 8. It becomes possible. In addition, although various electroconductive structural materials can be used as the support body 22, in this Embodiment, it is a general purpose H-section steel, for example.

  A substantially disk-shaped lid body 30 having an opening at the center is provided on the upper surface of the soot tube 13. Between the lower surface of the lid 30 and the upper surface of the soot tube 13, a lid seal member 31 is inserted as a first seal member that comes into airtight contact with the lid 30 and the soot tube 13. As the lid seal member 31, for example, silicon rubber packing is used in consideration of the high temperature of the by-product gas. Between the suspension tube 23 penetrating the opening of the lid 30 and the inner peripheral surface of the opening of the lid 30, a suspension tube sealing member 32 that comes into airtight contact with the lid 30 and the suspension tube 23 is provided. Is provided. Therefore, the upper surface of the tub tube 13 is airtightly closed by the lid body 30. The suspension pipe seal member 32 is a general-purpose gland packing, for example. Moreover, although the soot tube 13 is a substantially conical cylinder in FIG. 3, it may be cylindrical.

  Between the lower surface of the soot tube 13 and the upper surface of the main body structure portion 2, an annular soot tube receiver 33 having an open top is provided, and the soot tube 13 and the soot tube receiver 33 are applied to the top surface of the soot tube receiver 33 in an airtight manner. A soot tube seal member 34 is provided as a second seal member to be contacted. The lower surface of the soot tube receiver 33 is connected to the upper surface of the main body structure portion 2 by, for example, seal welding, so that by-product gas in the dust collecting chamber 6 is placed outside the soot tube 13 from between the main body structure portion 2 and the soot tube receiver 33. It has a structure that does not leak. Therefore, the inside of the soot tube 13, that is, the dust collecting chamber 6 side, and the outside of the soot tube 13, that is, the insulator chamber 11 side are hermetically separated by the soot tube sealing member 34 and the lid 30, and flow in the dust collecting chamber 6. The by-product gas is configured not to leak to the outside of the soot tube 13.

  Further, a push bolt 35 provided on the support 22 is in contact with the upper surface of the lid 30. A spring 37 is provided as an elastic body between the nut 36 of the push bolt 35 and the support body 22, and the spring 37 causes the push bolt 35 to move downward on the upper surface of the lid body 30, that is, toward the body structure portion 2 side. Is pressing. For this reason, the lid seal member 31 and the soot tube seal member 34 inserted between the lid body 30 and the soot tube 13 and between the soot tube 13 and the main body structure portion 2 are pressed by the spring 37, thereby the dust collecting chamber. The sealing property between 6 and the insulator chamber 11 is further enhanced. Further, even when a high temperature by-product gas flows into the dust collection chamber 6 and the main body structure 2 expands due to the heat of the by-product gas, the thermal expansion is absorbed by the spring 37 and so-called self-alignment is performed. Therefore, the lid seal member 31 and the soot tube seal member 34 can keep a stable contact following the thermal expansion, and even if the temperature of the main body structure portion 2 changes, the byproduct gas from the inside of the soot tube 13 Is configured not to leak. In the present embodiment, for example, as shown in FIG. 4, eight push bolts 35 are provided on the concentric circle of the lid 30. However, if the lid 30 can be appropriately pressed, the number is 8 or less. It may be eight or more. Further, when the outer diameter dimension of the lid body 30 is larger than the width of the support body 22 and the push bolts 35 cannot be evenly arranged, a support plate 22a is provided on the support body 22, and the spring of the push bolt 35 is supported by the support plate 22a. You may make it receive 37 reaction force.

  A heating device 40 is provided on the outer surface of the soot tube 13 over the entire circumference. By heating the soot tube 13, moisture in the by-product gas is condensed on the inside surface of the soot tube 13, and the moisture causes the soot tube to be condensed. Is prevented from occurring. The outer surface of the heating device 40 is covered with a heat insulating material (not shown) in order to enhance the effect of the heating device 40. As the heating device 40, for example, an electric heater or a steam heater can be used. In addition, from the viewpoint of preventing dielectric breakdown of the insulator tube 13, it is necessary to prevent moisture from adhering to the outer surface of the insulator tube 13, that is, the surface on the insulator chamber 11 side. Nitrogen supplied from the source is enclosed.

  The protective cylinder 14 has an inert gas header 50 which is provided over the entire outer periphery of the protective cylinder 14 and is hollow and formed in an annular shape. The inert gas means a gas that does not oxidize with the by-product gas that is a flammable gas, that is, has no risk of ignition even if mixed with the by-product gas. For example, helium, argon, carbon dioxide Alternatively, nitrogen or the like can be used, but it is preferable to use inexpensive nitrogen. In the protective cylinder 14, a slit-shaped opening 50 a communicating with the inert gas header 50 is provided at the center of the inert gas header 50 in the height direction in the region surrounded by the inert gas header 50. 14 are formed over the entire circumference. For this reason, the protective cylinder 14 is divided into an upper protective cylinder 14a and a lower protective cylinder 14b by a slit-shaped opening 50a, and the inert gas header 50 has an upper protection so as to straddle the slit-shaped opening 50a. The entire circumference is connected to the cylinder 14a and the lower protective cylinder 14b by seal welding. The inert gas header 50 is provided with an inert gas supply pipe 51 that communicates with the inside of the inert gas header 50 and supplies an inert gas. By supplying the inert gas into the header 50, the inert gas can be blown out from the slit-shaped opening 50 a over the outer peripheral surface of the suspension pipe 23. The inert gas supply pipe 51 is provided with a flow rate adjusting mechanism (not shown) for adjusting the supply amount of the inert gas to be constant. For example, an orifice or a needle valve can be used as the flow rate adjusting mechanism. It should be noted that the height H of the slit-like opening 50 a is formed to be uniform over the entire circumference of the protective cylinder 14 in order to blow out the inert gas uniformly over the entire outer periphery of the suspension tube 23. The inert gas supply pipe 51 is preferably provided at a right angle to the tangential direction of the outer peripheral surface of the inert gas header 50 as shown in FIG. Moreover, the shape of the opening 50a is not limited to the above-mentioned slit shape, and if the inert gas can be blown uniformly to the outer peripheral surface of the suspension tube 23, for example, the opening 50a has a plurality of openings 50a. May be.

  Above the inert gas header 50 and on the outer surface of the protective cylinder 14, a flange portion 14 c that supports the protective cylinder 14 is provided, and the upper surface of the flange portion 14 c is supported by the lower surface of the main body structure portion 2.

  The soot pipe fouling prevention apparatus 12 according to the present embodiment is configured as described above. Next, processing of by-product gas by the electric dust collector 1 having the soot pipe fouling prevention apparatus 12 will be described.

  First, as a preparatory work before the by-product gas is introduced into the electrostatic precipitator 1, an inert gas header (not shown) is previously connected to the inside of the inert gas header 50 through the inert gas supply pipe 51. Supply active gas. As shown in FIG. 5, the inert gas supplied to the inert gas header 50 is blown out horizontally from the slit-like opening 50a of the inert gas header 50 at a predetermined flow rate, and is suspended vertically while diffusing vertically. Reach the outer peripheral surface of. The inert gas blown out horizontally forms a gas seal layer that seals the inside of the vertical tube between the outer peripheral surface of the suspension tube 23 and the inner surface of the protective cylinder 14.

  In parallel with the supply of the inert gas to the inert gas header 50, the soot tube 13 is heated by the heating device 40, a high voltage current is supplied to the discharge electrode 8, and a spray nozzle (not shown) is supplied to the dust collection electrode 7. Spray water for cleaning. Thereby, the preparatory work before by-product gas introduction is completed.

  Next, when the by-product gas from the converter flows into the dust collecting chamber 6 through the gas inlet 4 of the electric dust collector 1, the dust in the by-product gas is charged to a negative charge by the discharge from the discharge electrode 8. And it is collected by the dust collection electrode 7 which is a positive electrode. At this time, dust that is not collected by the dust collecting electrode 7 exists in the vicinity of the protective cylinder 14 at the upper part of the dust collecting chamber 6, but a gas seal layer is formed between the protective cylinder 14 and the suspension pipe 23. As a result, dust does not enter the tub tube 13. In addition, since the upper surface of the soot tube 13 and the space between the soot tube 13 and the main body structure portion 2 are closed in an airtight manner, the inert gas blown out toward the outer peripheral surface of the protective cylinder 14 flows out of the soot tube 13. Instead, as shown in FIG. 3, the flow flows downward 52 into the dust collection chamber 6 from the inside of the protective cylinder 14. Therefore, since the inside of the protective cylinder 14 is also sealed by the downward flow 52, the dust in the by-product gas does not adhere to the inner surface of the protective cylinder 14. In addition, the sealing performance of the gas seal layer by the inert gas blown out from the slit-like opening 50a of the inert gas header 50 is the flow rate of the blown inert gas, the distance between the protective cylinder 14 and the suspension pipe 23, or the dust collection. It varies depending on various conditions such as the pressure of by-product gas in the chamber 6. For this reason, a flow rate at which a necessary sealing performance is obtained is obtained in advance by a model test or fluid analysis simulation on a reduced scale, and a necessary supply amount of the inert gas is determined in advance from the flow rate.

  The dust collected by the dust collecting electrode 7 is washed away by the water sprayed from the spray nozzle toward the dust collecting electrode 7, and together with the water, passes through the hopper 15 at the lower part of the main body structure portion 2 and is discharged from the electric dust collector 1. It is discharged out of the system. The byproduct gas from which dust has been removed in the dust collection chamber 6 is discharged from the gas outlet 5.

  According to the above embodiment, the gas seal layer that seals the inside of the vertical pipe is formed by the inert gas blown from the slit-shaped opening 50a of the inert gas header 50 toward the outer peripheral surface of the suspension pipe 23. Therefore, it is possible to prevent dust from entering the inside of the soot tube 13. Further, since the upper surface of the soot tube 13 is airtightly closed and the inert gas does not flow out from the top of the soot tube 13, the inert gas blown out from the opening 50 a flows downward in the protective cylinder 14. A flow 52 is formed. For this reason, the inside of the protective cylinder 14 can be simultaneously sealed by the downward flow 52, and the inert gas to be supplied can be suppressed to the minimum amount necessary for sealing the inside of the protective cylinder 14. Therefore, by using the soot tube fouling prevention device 12 of the present invention, it is possible to prevent dust from adhering to the soot tube 13 and the protective cylinder 14 without requiring a large inert gas supply facility. Accordingly, the electrostatic precipitator 1 can be stably operated over a long period of time without periodically cleaning the inside of the electrostatic precipitator 1.

  Further, when nitrogen is used as the inert gas, for example, nitrogen is a dry gas having a dew point temperature of minus several tens of degrees. Therefore, by enclosing the inert gas in the soot tube 13, for example, some trouble is caused in the heating device 40. Even when the soot tube 13 cannot be heated, it is possible to prevent moisture condensation on the inside surface of the soot tube 13.

  According to the above embodiment, the lid seal member 31 provided between the lid body 30 and the soot tube 13 and the soot tube seal member 34 provided between the soot tube 13 and the main body structure portion 2 are provided with the push bolts. Since it is pressed by 35, the dust collection chamber 6 and the insulator chamber 11 can be reliably and hermetically isolated by the soot tube 13. Further, even when the by-product gas is introduced into the dust collection chamber 6 and the main body structure portion 2 expands due to the heat of the by-product gas, the thermal expansion is absorbed by the spring 37 and so-called self-alignment is performed. For this reason, the lid seal member 31 and the soot tube seal member 34 can maintain a stable contact state following the thermal expansion. Therefore, even when the temperature of the main body structure portion 2 changes, no by-product gas or inert gas leaks from the inside of the soot tube 13 to the outside of the soot tube 13.

  In the above embodiment, the supply amount of the inert gas to the inert gas header 50 is constant, but the flow rate control capable of controlling the supply amount of the inert gas in proportion to the flow rate of the by-product gas flowing in. Means may be provided in the inert gas supply pipe 51. In that case, a control device for monitoring the flow rate of the by-product gas may be provided, and the flow rate control means may be automatically controlled by the control device. Further, when the flow rate of the by-product gas decreases and the gas flow rate in the dust collection chamber 6 decreases, dust does not adhere to the inner surfaces of the soot tube 13 and the protective cylinder 14 even if the supply of the inert gas is stopped. For example, the inert gas supply pipe 51 may be provided with a shut-off mechanism that automatically monitors the flow of the by-product gas and automatically shuts off the supply of the inert gas when the flow rate becomes a predetermined flow rate or less.

  In the above embodiment, the inside of the inert gas header 50 is hollow, and the inert gas blown out from the slit-shaped opening 50a is directed toward the center of the suspension tube 23. For example, FIG. As shown in FIG. 6, the inert gas supply pipe 70 is provided so as to be supplied along the circumferential direction of the inert gas header 71, that is, along the tangential direction of the circumference of the inert gas header 71. A swirling flow may be formed inside 71. In such a case, the inert gas blown out from the opening 50 a forms a swirling flow in the protective cylinder 14 due to the swirling flow in the inert gas header, and the same effect as the gas seal layer by the inert gas header 50 is obtained. In this case, in order to form a swirl flow more reliably, it is preferable to provide a plurality of inert gas supply pipes 70 facing each other with the inert gas header 71 interposed therebetween. Further, as shown by a broken line in FIG. 6, the rectifying plate 72 as a rectifying member may be installed at a predetermined angle A with respect to the discharge direction of the inert gas from the inert gas supply pipe 70. In this case, the swirl force of the swirl flow can be increased as compared with the case where the rectifying plate 72 is not provided.

  In the above embodiment, a so-called wet electric dust collector in which dust collected on the dust collecting electrode 7 is washed away with water has been described as an example, but the soot fouling prevention device 12 of the present invention is limited to such an example. Not only in the so-called dry-type electrostatic precipitator that separates dust collected by the precipitator 7 by striking the precipitator 7, but also in the vertical electrostatic precipitator for treating by-product gas from the coke oven It can be used. Moreover, in the electric dust collector which processes the gas which does not contain combustible gas in exhaust gas, such as coal combustion equipment of a power plant, it may change to an inert gas, for example, may use the heated air.

  Hereinafter, as an example, the internal fluid analysis of the soot tube 13 and the protective cylinder 14 when the soot tube fouling prevention device 12 of the present invention is used for the electrostatic precipitator 1 is carried out by simulation. Based on the simulation results, the assembly structure and operation of the actual machine are performed. An internal flow visual confirmation test simulating the conditions was performed. Hereinafter, the effect of preventing the adhesion of dust to the inner surface of the soot tube 13 in the embodiment will be described. In this embodiment, the soot tube fouling prevention device 12 having the inert gas header 71 shown in FIG. 6 was used, and nitrogen was used as the inert gas.

The operating conditions of the electrostatic precipitator 1 are as follows: the processing gas amount is 75,000 Nm ³ / hr dry, the processing gas temperature is 70 degrees, the water in the processing gas is saturated, the processing gas pressure is a maximum of 700 mmAq, and the normal processing is 350 mmAq. Table 1, the dust composition in the processing gas is shown in Table 2, the particle size distribution of the dust is shown in Table 3, and the bulk specific gravity of the dust is 2.5 g / cm ³ . In addition, the dust collection efficiency of the electrostatic precipitator is 93.75% (electrostatic precipitator inlet dust concentration 80 mg / Nm ³ , outlet dust concentration 5 mg / Nm ³ Dry).

At that time, the soot tube 13 was an upper outer diameter φ265 mm, a lower outer diameter φ430 mm, a height of 500 mm, and the material was a cordierite-type porcelain soot tube. The protective cylinder 14 had an outer diameter φ318.5 mm, a length of 90 mm from the upper end of the main body structure 2 to the upper end of the protective cylinder 14, and a length of about 500 mm from the lower end of the main body structure 2 to the lower end of the protective cylinder 14. As a result, the installation position of the inert gas header 71 is about 80 mm from the lower end of the soot tube 13 of the protective cylinder 14, the angle A of the rectifying plate 72 is about 30 degrees, and the nitrogen supply amount per place of the soot tube 13 is about 0.2 m ^3. A simulation result of / min was obtained.

  Based on this result, an internal flow visual confirmation test was performed that simulated the assembly structure and operating conditions of the actual machine. As a result, no adhesion of dust to the inside of the soot tube 13 and the inside of the protective cylinder 14 was observed, and it was confirmed that the soot pipe fouling prevention device 12 of the present invention was effective for preventing dust from adhering inside the soot pipe 13 and the protective cylinder 14. . In addition, a heating device 40 is provided in the cone-shaped portion of the soot tube 13, a heat insulating material is applied to the installation range of the warming device 40 and the upper end thereof, and steam of about 175 degrees is supplied to the heating device 40, A test of 13 heatings was performed simultaneously. As a result, it was confirmed that dew condensation and moisture adhesion inside the pipe 13 can be prevented.

   The present invention relates to a part in which a high voltage conductor for a discharge electrode penetrates a housing of a dust collector in an electric dust collector for flammable gas and toxic gas such as fuel gas, which requires particularly high facility reliability in terms of safety and disaster prevention. It can be used as a device for preventing dielectric breakdown due to condensation or fouling of insulators installed in the building.

DESCRIPTION OF SYMBOLS 1 Electrostatic precipitator 2 Main body structure part 3 Frame 4 Gas inlet 5 Gas outlet 6 Dust collection chamber 7 Dust collection electrode 8 Discharge electrode 9 Hopper 10 High voltage supply lead 11 Insulator chamber 12 Dust tube fouling prevention device 13 Dust tube 14 Protection cylinder 14a Upper protection cylinder 14b Lower protective cylinder 14c Flange part 20 Base 21 Support insulator 22 Support body 22a Support plate 23 Suspension pipe 30 Cover body 31 Cover body seal member 32 Suspension pipe seal member 32a Seal member presser 33 Saddle tube receiver 34 Saddle tube seal member 35 Push bolt 36 Nut 37 Spring 40 Heating device 50 Inert gas header 50a Opening 51 Inert gas supply pipe 52 Downflow 70 Inert gas supply pipe 71 Inert gas header 72 Rectifier plate

Claims (7)

An antifouling device for a soot tube disposed around a suspension tube that suspends a discharge electrode disposed in a main body structure of an electric dust collector,
The soot tube is provided on the upper surface of the main body structure portion of the electric dust collector,
A lid for airtightly closing the upper surface of the tubule;
A protective cylinder that is provided on the lower surface of the main body structure portion and is disposed around the suspension pipe, below the vertical pipe.
The lower surface of the soot tube is provided airtight with the upper surface of the main body structure part,
In the protective cylinder, an opening for supplying an inert gas toward the periphery of the suspension pipe is formed,
The upper surface of the soot tube and the bottom surface of the soot tube are a first seal member provided between the soot tube and the lid, and a second seal member provided between the main body structure portion and the soot tube. Are airtightly closed by being pressed by a plurality of elastic bodies that are supported by a support provided above the lid and are in contact with the upper surface of the lid. A fistula antifouling device. An annular inert gas header provided in a region facing the opening on the outer peripheral surface of the protective cylinder, and supplying the inert gas to the opening;
The soot pipe fouling prevention apparatus according to claim 1, further comprising an inert gas supply pipe that supplies the inert gas to the inert gas header. The said opening is provided in the shape of a slit over the perimeter of the inner surface of the said protection cylinder, The fistula antifouling apparatus in any one of Claim 1 or 2 characterized by the above-mentioned. The said inert gas supply pipe | tube is provided so that the said inert gas may be supplied along the circumferential direction of the said inert gas header, The Claim 1 characterized by the above-mentioned. Pipe tube antifouling device. The said inert gas header has the rectification | straightening member provided incline with the predetermined angle with respect to the discharge direction of the inert gas from the said inert gas supply pipe | tube, It is characterized by the above-mentioned. Anti-fouling device for tubules. 6. The soot tube fouling prevention device according to any one of claims 1 to 5, wherein a heating device is provided on an outer peripheral portion of the soot tube. The fistula fouling prevention device according to any one of claims 1 to 6, wherein the inert gas is nitrogen.

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