JP2018176132A - Bag filter device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bag filter device which can more further effectively suppress deliquescence of particulate matters.SOLUTION: A hopper part 3 of a bag filter device 1 for dust removal of a gas is configured from a casing wall 30 which blocks internal atmosphere, and a thermal insulation material wall 31 for thermal insulation outside the casing wall 30. A heater 35 is so tightly fitted to an external surface of the casing wall 30. By keeping a temperature of a wall surface (the casing wall 30) of the hopper part 3 constant, deliquescence of particulate matters can be further effectively suppressed. For example, a sheathed heater is used as the heater 35.SELECTED DRAWING: Figure 1

Description

  BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a bag filter apparatus having a function of suppressing the deliquescence of dust.

  For example, the bag filter device for removing the exhaust gas from the waste treatment furnace is provided with a hopper unit for receiving dust collected and dropped by the bag filter and supplying it to the lower discharge mechanism. When the dust adhering to the hopper deliquesces, the acid component in the gas dissolves in the deliquescent dust, causing a problem of corroding the wall of the hopper.

  Therefore, conventionally, there is known a means for preventing deliquescence by installing a desiccant inside the hopper section when the operation of the bag filter device is stopped (Patent Document 1). Also, it is considered to install a heater on the outer wall of the bag filter. For example, a means for keeping warm by winding a heating wire to an outer wall or circulating warm air to an outer wall surface is known (Patent Document 2).

JP-A-8-323146 Unexamined-Japanese-Patent No. 2001-347120

  However, at the time of operation and stop of the bag filter device, the exhaust gas stagnates in the hopper portion. In the techniques of Patent Documents 1 and 2 described above, the effect is limited, and there is a problem that deliquescence occurs.

  The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a bag filter device capable of more effectively suppressing the deliquescence of dust.

  As a result of intensive research conducted by the inventor in order to solve the above problems, it has been found that generation of deliquescence can be effectively suppressed by keeping the temperature of the wall surface of the hopper portion constant.

  According to the present invention, the hopper portion of the bag filter device for removing the exhaust gas is constituted by the casing wall that shuts off the internal atmosphere and the heat insulating material wall that insulates the outside of the casing wall. A bug filter device is provided, characterized in that it is mounted.

  In the bag filter device of the present invention, the heater is, for example, a sheathed heater.

  According to the present invention, it is possible to more effectively suppress the deliquescent of dust by maintaining the temperature of the wall surface of the hopper portion constant in the bag filter device.

It is explanatory drawing of the bug filter apparatus concerning the Example of this invention. It is a partial expanded sectional view of the hopper part comprised by double structure. It is a bottom view of a hopper part. It is a side view of the hopper part seen in the X direction in FIG. It is a side view of the hopper part seen in the Y direction in FIG. It is a partial expanded sectional view of a hopper part for explaining a comparative example. It is a graph which shows the temperature change of the hopper part in the bag filter apparatus concerning the Example of this invention. It is a graph which shows the temperature change of the hopper part in the bug filter apparatus concerning a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration will be assigned the same reference numerals and redundant description will be omitted.

  The exhaust gas burned in a combustion furnace or a melting furnace is sprayed with water droplets and cooled to an appropriate temperature, and then a powdered chemical is sprayed and supplied into the bag filter device 1 shown in FIG. The bag filter device 1 has a prismatic housing 2 at the upper portion, and a quadrangular pyramid hopper portion 3 is continuously formed from the housing 2 at the lower portion. An inlet 4 is formed on the side wall of the housing 2, an inlet duct 5 is connected to the inlet 4, and exhaust gas containing dust, heavy metals, etc. (dust a) is introduced through the inlet duct 5 and the inlet 4. It is introduced into the housing 2.

  At an upper portion of the housing 2, a discharge port 10 is provided for discharging the processing gas which has been subjected to filtration, dust removal and purification of a predetermined component to the outside. A discharge duct 11 is connected to the discharge port 10, and the processing gas is discharged from the discharge duct 11 to the outside through the chimney 13 by the operation of the intake fan 12.

  Inside the housing 2, a plurality of bag filters 15 are installed. The bag filter 15 is made of a cylindrical filter cloth which is open only at the upper side. The bag filter 15 is made of chemical fiber, for example, and has a filtration layer corresponding to the removal component. The exhaust gas that has flowed into the housing 2 passes through the bag filter 15, whereby predetermined components (dust and dirt a) such as dust and heavy metals are filtered and removed. An upper end of the bag filter 15 is suspended by a beam 16 horizontally installed in the housing 2.

  In the housing 2, a mechanism for removing dust a attached to the bag filter 15 is provided. As a specific example, as illustrated, the air pipe 21 connected to the pulse generator 20 is disposed above the bag filter 15. The air pipe 21 is provided with an injection valve 23 directed to the upper opening 22 of each bag filter 15. As a result, high pressure air is jetted from the upper opening 22 of the bag filter 15 toward the inside of the bag filter 15, and the impact force and the induced reverse air flow remove dust a attached to the outside of the bag filter 15. The means for removing the dust a is not limited to this method, and may be, for example, a swing type.

  At the lower end of the hopper portion 3, a discharge port 26 provided with a discharge valve 25 for discharging the discharged dust a to the outside is provided. The dust a is dropped from the hopper portion 3 through the discharge port 26 by the opening and closing of the discharge valve 25, and is supplied to the lower discharge mechanism 27.

  As shown in FIG. 2, the hopper portion 3 has a double structure including a casing wall 30 disposed inside and a heat insulating material wall 31 disposed outside. The casing wall 30 plays a role of blocking the internal atmosphere (the internal atmosphere of the housing 2) of the hopper portion 3 and is made of, for example, a steel plate. The heat insulating material wall 31 insulates on the outside of the casing wall 30. A constant air gap 32 is provided between the casing wall 30 and the heat insulating material wall 31.

  A plurality of heaters 35 are attached to the outer surface of the casing wall 30. The plurality of heaters 35 are attached in close contact with the outer surface of the casing wall 30 in the inside of the gap 32.

  For example, a sheathed heater is used as the heater 35. As an example of a product used for heater 35, brand name "hopper heater" and model "HH type" made by Nippon Heater Co., Ltd. can be raised.

  As shown in FIGS. 3 to 5, the plurality of heaters 35 are uniformly distributed over the entire outer surface of the casing wall 30, and are heated by the plurality of heaters 35 attached in intimate contact with the outer surface. , The entire casing wall 30 is to be heated to approximately the same temperature.

  Next, an outline of the procedure for dust removal treatment of exhaust gas by the bag filter device 1 having the above configuration will be described.

  An exhaust gas generated by the combustion of a combustion furnace, a melting furnace or the like is introduced into the housing 2 from the introduction port 4 through the introduction duct 5. The exhaust gas flows in the direction of the arrow in FIG. 1 in the housing 2 and contacts the outside of the bag filter 15. When the exhaust gas passes from the outside to the inside of the bag filter 15, dust, heavy metals and the like (dust and dirt a) contained in the exhaust gas adhere to the bag filter 15 to be removed and filtered, and the exhaust gas becomes a clean gas. The clean gas thus dusted and filtered flows from the top opening 22 of the bag filter 15 to the top of the housing 2 and is discharged from the discharge port 10 to the outside through the discharge duct 11, the intake fan 12 and the chimney 13.

  In the case where a certain amount or more of dust a adheres to the surface of the bag filter 15, compressed air is jetted from the upper opening 22 of the bag filter 15 toward the inside of the bag filter 15, and the dust a is removed. The dust a discharged in this manner falls into the lower hopper portion 3.

  When the dust a is accumulated in a fixed amount or more in the hopper portion 3, the discharge valve 25 is opened and closed, and the dust a drops from the hopper portion 3 through the discharge port 26 and is supplied to the discharge mechanism 27 below.

  Here, in the bag filter device 1, when the dust a attached to the hopper portion 3 deliquesces, the acid component in the gas dissolves in the deliquesed dust a and causes a problem that the wall surface of the hopper portion 3 is corroded.

  However, in the bag filter device 1 according to this embodiment, the plurality of heaters 35 uniformly distributed over the entire outer surface of the casing wall 30 and disposed in close contact with each other makes the entire casing wall 30 have substantially the same temperature. It is heated. For this reason, the dust a adhering to the hopper portion 3 is not wetted, and the deliquescence of the dust a is prevented. As a result, wall surface corrosion of the hopper portion 3 can be avoided.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to this form. It is apparent that those skilled in the art can conceive of various changes or modifications within the scope of the technical idea described in the claims, and the technical scope of the present invention is also natural for them. It is understood to belong to

  For example, the heater 35 is not limited to the sheathed heater but may be another heater. Further, the temperature of the casing wall 30 is controlled to be not less than + 5 ° C. and not more than T + 20 ° C. with respect to the deliquescence temperature T of the dust a by the plurality of heaters 35 disposed evenly distributed over the entire outer surface of the casing wall 30. Is desirable.

  The dust removal process of the exhaust gas was performed based on the bag filter device 1 of the above embodiment. The hopper portion was formed into a quadrangular pyramid having a bottom of 4300 mm × 3671 mm, and the casing wall was heated by a plurality of heaters attached closely to the entire outer surface of the casing wall. Since the main component of the dust is calcium chloride, the deliquescence temperature is about 75 ° C. Therefore, the temperature of the casing wall was controlled to be 95.degree.

  On the other hand, in the comparative example, as shown in FIG. 6, the heater 35 is placed close to the heat insulating material wall 31 in the inside of the void 32 without heating the heater 35 in close contact with the outer surface of the casing wall 30. The

  About the Example and comparative example of this invention, temperature measurement was each performed by six places (thermometer 1-6) of a casing wall, and the temperature change of each thermometer 1-6 was investigated. As a result, as shown in FIG. 7, in the example of the present invention, the temperatures measured by the thermometers 1 to 6 were all able to maintain the deliquescent prevention temperature (75 ° C. or higher). On the other hand, as shown in FIG. 8, in the comparative example, the temperature measured by each of the thermometers 1 to 6 is not stable, and in particular, the temperature measured by the thermometer 4 is a deliquescent prevention temperature (75 ° C. or more) Could not keep up. In addition, the embodiment of the present invention can realize reduction of power (9464 W to 2752 W) as compared with the comparative example.

a dust dust 1 bag filter device 2 housing 3 hopper portion 4 inlet 5 introduction duct 10 outlet 11 discharge duct 12 intake fan 13 chimney 15 bug filter 16 beam 20 pulse generator 21 air pipe 22 upper opening 23 injection valve 25 discharge valve 26 Discharge port 27 Discharge mechanism 30 Casing wall 31 Thermal insulation wall 32 Air gap 35 Heater

Claims (2)

The hopper portion of the bag filter device for removing exhaust gas is composed of a casing wall for blocking the internal atmosphere and a heat insulating wall for heat insulation outside the casing wall,
A bag filter apparatus, wherein a heater is attached to the outer surface of the casing wall.   The bag filter device according to claim 1, wherein the heater is a sheathed heater.

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