Dust remover

Abstract

To provide a dust remover that can maintain appropriate dust removing performance for a long time.SOLUTION: A dust remover is constituted to comprise: wet-type filter panels 6 on which a collection layer is formed of collection liquid and which are fed to an air passage to collect solid particles in the air; a liquid tank 3 that stores the collection liquid and immerses the filter panels 6 into the collection liquid; and washing prompting devices 7 provided with gas feeding parts 7a that feed gas to the filter panels 6 immersed into the collection liquid in the liquid tank 3, from below.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an apparatus for removing dust from air supplied to facilities and equipment that require air intake, particularly under conditions where the air contains a large amount of dust, such as in the surrounding areas after a volcanic eruption.

Background Art

[0002] Generally, in facilities and equipment equipped with devices that require air for operation, such as gas turbines and internal combustion engines, a dust removal device equipped with a filter is provided at the air intake, and the dust-removed air is supplied to the device.

[0003] Examples of prior art documents related to this type of dust removal device include Patent Documents 1 to 3 below.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, for example, when a volcanic eruption or the like occurs, volcanic ash is released into the air, and in some cases, a large amount of dust is contained in the air in the form of volcanic ash due to the fallout. In such a case, the dust removal device will operate under extremely high-load conditions, and depending on the performance of the dust removal device, it may become difficult to continue the operation of a gas turbine, an internal combustion engine, or the like, which is the destination of the air supply. Even if the dust removal performance of the dust removal device itself (the amount of dust that can be removed per unit time, or the amount of dust removal air that can be supplied per unit time) is sufficient, since the amount of dust adsorbed per unit time is enormous, frequent filter replacement and cleaning are required, and each time, it may be necessary to stop the operation of a gas turbine, an internal combustion engine, or the like. Therefore, under such high-load conditions, a dust removal device that can continuously perform sufficient dust removal for a long time has been demanded.

[0006] In view of such circumstances, the present invention aims to provide a dust removal device that can maintain suitable dust removal performance for a long time.

Means for Solving the Problem

[0007] The present invention relates to a dust removal device comprising: a wet filter having a collection layer formed by a collection liquid on its surface and being sent through an air flow path to collect solid particles in the air; a liquid tank for storing the collection liquid and immersing the filter in the collection liquid; and a cleaning promotion device provided with an air supply unit for sending gas from below to the filter immersed in the collection liquid in the liquid tank.

[0008] In the dust removal device of the present invention, the cleaning promotion device may further include a support unit for supporting the filter immersed in the liquid tank at an inclined angle.

[0009] The dust removal device of the present invention may be configured to include a liquid treatment device for separating solid particles from the collection liquid mixed with solid particles drawn out from the liquid tank, and the collection liquid from which the solid particles have been separated can be returned from the liquid treatment device to the liquid tank.

Effect of the Invention

[0010] According to the dust removal device of the present invention, it is possible to achieve an excellent effect of maintaining suitable dust removal performance for a long time.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0013] FIG. 1 shows an example of the form of a dust removal device according to the implementation of the present invention. The dust removal device 100 is formed by providing a wet continuous regeneration filter device 1 in the middle of a duct that forms an air flow path. The duct is configured to include, in order from the upstream side, an inlet duct (primary dust removal duct) 10, a pre-filter chamber (secondary dust removal chamber) 20, a filter chamber 30, a post-filter chamber (tertiary dust removal chamber) 40, and an outlet filter chamber 50. Among these, the continuous regeneration filter device 1 is installed in the filter chamber 30, and a dry post-filter 51 is installed in the outlet filter chamber 50. In the secondary dust removal chamber 20 corresponding to the upstream side of the continuous regeneration filter device 1, a flow rate adjustment unit 21 for controlling the air flow rate in the entire dust removal device 100 is installed, and a dust monitor 41 is installed in the tertiary dust removal chamber 40 corresponding to the downstream side of the continuous regeneration filter device 1. A liquid treatment device 60 for recovering the oil after adsorbing solid particles in the air in the continuous regeneration filter device 1 and supplying clean oil is connected to the continuous regeneration filter device 1. The downstream side of the outlet filter chamber 50 is connected to a facility 200 such as a gas turbine generator or an internal combustion engine that requires air supply, and the air dust-removed through the dust removal device 100 is supplied to the facility 200. The power for driving the air flow from the inlet duct 10 through the outlet filter chamber 50 to the facility 200 is provided by the air suction in the facility 200 (for example, in a gas turbine generator, a large amount of air is inhaled during operation), but a fan or the like for assisting the air circulation may be provided as needed.

[0014] The inlet duct (primary dust removal duct) 10 is, for example, a vertical duct with an inlet at the bottom and an outlet at the top. Solid particles such as volcanic ash contained in the air are held in the air by the balance between the weight of the solid particles and the buoyancy force of the flowing air. That is, if the force trying to fall due to its own weight exceeds the force trying to rise due to buoyancy, the solid particles cannot stay in the air and fall. In the primary dust removal duct 10, while flowing through the primary dust removal duct 10, the solid particles that can no longer float in the air due to buoyancy fall and are removed from the air. Note that the configuration of the primary dust removal duct 10 shown in FIG. 1 is merely an example, and the orientation of the primary dust removal duct may be horizontal, for example, or in the case of a vertical one, an inlet may be provided at the top and an outlet may be provided at the bottom. Alternatively, for the purpose of, for example, causing the air to collide with the inner wall for dust removal or adjusting the air flow velocity by pressure loss, the primary dust removal duct itself may be provided with a bent shape. Also, a structure such as a baffle plate may be appropriately provided inside to cause the air to collide to remove solid particles or to adjust the air flow velocity, direction, etc.

[0015] The pre-filter chamber (secondary dust removal chamber) 20 is a part that constitutes the flow path in the front stage of the continuous regeneration filter device 1 and is, for example, a horizontal duct. However, regarding the specific duct shape, etc., it may be appropriately changed in the implementation of the dust removal device. The secondary dust removal chamber 20 plays a role of adjusting the amount of air supplied to the continuous regeneration filter device 1 after passing through the primary dust removal duct 10 to an appropriate range for the continuous regeneration filter device 1. Regarding the duct shape, length, cross-sectional area, etc., it is appropriately designed so that an appropriate amount of air flows through. Also, a structure such as a straightening plate or a throttle may be provided as necessary.

[0016] Near the entrance in the secondary dust removal chamber 20, a flow rate adjustment unit 21 for further adjusting the air flow rate is provided. The flow rate adjustment unit 21 is a device such as a louver, shutter, or damper, and adjusts the pressure loss by adjusting the opening degree to adjust the amount of air flowing downstream. The required flow rate of the air to be dust-removed varies according to the operating conditions of the downstream equipment 200, etc. On the other hand, in the wet continuous regeneration filter device 1 as described later, the dust removal performance varies depending on the air flow rate. Specifically, the higher the air flow rate, the higher the removal efficiency (the ratio of solid particles that can be collected), while the lower limit of the particle diameter that can be efficiently removed becomes larger. Also, as will be described later, the dust removal amount of the continuous regeneration filter device 1 can also be adjusted by the filter feed speed in the continuous regeneration filter device 1. Therefore, while adjusting the filter feed speed in the continuous regeneration filter device 1, the air flow rate is adjusted by the flow rate adjustment unit 21 to adjust the air flow rate to a speed suitable for the continuous regeneration filter device 1, maintain the air cleanliness, and supply the required amount of air to the equipment 200.

[0017] In the filter chamber 30, a continuous regeneration filter device 1 is provided. The continuous regeneration filter device 1 in this embodiment is the same device as the collision adhesion type air cleaning device described in the above Patent Document 3, and includes a filter unit 2 and a liquid tank 3 as shown in FIGS. 2 and 3.

[0018] The filter unit 2 is configured to include a plurality of filter panels 6 having an elongated rectangular shape extending along the lateral direction. Both ends of each filter panel 6 are attached to a pair of endless chains 4 at both ends in the longitudinal direction. Here, each filter panel 6 is rotatably attached to the chain 4 around a rotation axis along the longitudinal direction at one end side in the width direction (the short side direction of the rectangle) at the attachment portion to the chain 4, and when no external force is applied to the filter panel 6, it hangs down by its own weight from the chain 4.

[0019] Each chain 4 is wound around sprockets 5 arranged vertically above and below. The sprockets 5 are provided with a rotating shaft arranged along the horizontal direction and are adapted to rotate by a motor (not shown). Due to the rotation of the sprockets 5, a large number of filter panels 6 attached to the chain 4 reciprocate up and down around the sprockets 5. Since the sprockets 5 are arranged vertically and the chain 4 is wound around them, the filter panels 6 attached to the chain 4 overlap each other before and after the sprockets 5 and as a whole form a plane along the vertical direction before and after the sprockets 5.

[0020] The filter panel 6 is a metal member shaped like a rectangular frame with a plurality of louvers passed through it as shown in FIG. 6, for example. When the continuous playback filter device 1 is in operation, the air flow flows in a direction orthogonal to the plane along the vertical direction formed by a large number of filter panels 6. With respect to each filter panel 6, the air bypasses the louvers constituting each filter panel 6 and flows through the gaps between the louvers. At this time, at least a part of the solid particles contained in the air cannot follow the air flow due to inertia and collide with the louvers. The surface of the filter panel 6 is covered with oil as a collecting liquid for collecting solid particles, and the solid particles that collide with the filter panel 6 adhere to and are captured by the collecting layer formed by this oil. In such a type of filter panel 6, if the interval between the louvers is sufficiently wide with respect to the diameter of the solid particles, clogging will not occur and air can be purified with a very small pressure loss. Although not shown in the figure, the surface of the filter panel 6 is further provided with fine irregularities throughout, thereby ensuring the surface area and improving the collection efficiency.

[0021] Here, since one end side of each filter panel 6 in the short side direction is rotatably attached to the chain 4 as described above, if the sprocket 5 is rotated without providing a structure or the like that restricts the posture of each filter panel 6 with respect to the chain 4, in front of and behind the sprocket 5, each filter panel 6 will hang down from the chain 4 with the end that is not attached to the chain 4 (hereinafter referred to as the "free end") of both ends in the short side direction facing downward. In that case, looking from the air flow, each filter panel 6 will face the same surface in front of and behind the sprocket 5. That is, regarding the collection of solid particles, only one side of each filter panel 6 will be used.

[0022] Therefore, in the continuous regeneration filter device 1 of the present embodiment, a guide 8 is provided in the vicinity of the rotation range of the filter panel 6 by the sprocket 5 and the chain 4. The guide 8 is a rod-shaped member provided along the vertical direction so as to follow the surface formed by the filter panel 6 in front of and behind the sprocket 5.

[0023] In the case of this embodiment, in the filter unit 2, with respect to the air flow, the filter panel 6 on the front side of the sprocket 5 moves upward, and the sprocket 5 rotates in such a direction that the filter panel 6 on the rear side moves downward. In such rotation, the filter panel 6 lifted from the liquid tank 3 to the front side moves upward on the front side with respect to the sprocket 5 with its free end facing downward. Then, when passing above the sprocket 5, the filter panel 6 turns its free end upward, but when further turning to the rear, it tries to return to the posture of turning its free end downward again due to its own weight. Here, on the rear side of the filter panel 6, the above-described guide 8 is positioned along the filter panel 6. This guide 8 is positioned close enough to the chain 4 located on the rear side of the sprocket 5 and contacts the free end of the filter panel 6 to limit the rotation of the filter panel 6. Due to the presence of this guide 8, the filter panel 6 will move downward while keeping its free end facing upward. From the perspective of the air flow, the surface of the filter panel 6 facing the air flow on the front side of the sprocket 5 and the surface of the filter panel 6 facing the air flow on the rear side of the sprocket 5 are opposite to each other. That is, if the surface of the filter panel 6 facing the air flow on the front side of the sprocket 5 is regarded as the front surface, then on the rear side of the sprocket 5, it will face the back surface with respect to the air flow. In this way, while the filter panel 6 makes one full turn around the sprocket 5, both the front and back surfaces are used for collecting solid particles. When the filter panel 6 reaches the lower end of the rotation range, the filter panel 6 rotates away from the guide 8 and returns to the posture with its free end facing downward again.

[0024] Below the rotation range of the filter panel 6, a liquid tank 3 for storing oil as the collected liquid is provided. The filter panel 6 that reciprocates around the sprocket 5 by the rotation of the sprocket 5 is immersed in the oil in the liquid tank 3 below the rotation range. The filter panel 6 immersed in the oil and with oil adhering to the whole rises from the liquid tank 3 due to the rotation of the sprocket 5, and captures the solid particles in the air that collide therewith with the oil as described above. The filter panel 6 with solid particles adhering thereto while passing through the air flow path set outside the liquid tank 3 sinks again into the oil in the liquid tank 3 due to the rotation of the sprocket 5, the collected solid particles are washed off here, and at the same time, oil adheres again and the oil film forming the collection layer on the surface is updated. In this way, the filter panel 6 continuously circulates while being continuously sent to the air flow path, passes through the oil in the liquid tank 3 in the middle of the path, and the collection performance of the solid particles by the oil is continuously regenerated. The rotation speed of the sprocket 5 can be adjusted according to the flow rate of the air to be purified in the filter unit 2, the concentration of the solid particles contained in the air, and the like.

[0025] Note that the configuration of the continuous regeneration filter device 1 shown here is merely an example, and the present invention can be applied to various filter devices as long as they are continuous regeneration filter devices of a type that collect solid particles in a gas using a liquid.

[0026] Further, the liquid tank 3 is provided with a cleaning promotion device 7 for enhancing the cleaning ability of the filter panel 6 by the oil stored in the liquid tank 3. This cleaning promotion device 7 is a device having a configuration as described below, for example.

[0027] As shown in Fig. 4, the cleaning promotion device 7 includes an air supply section 7a that sends gas (air) into the oil stored in the liquid tank 3, and a support section 7b that supports the filter panel 6 immersed in the oil at an appropriate angle. The air supply section 7a is, for example, a tube through which air passes and a ventilation tube having holes (air supply holes) that communicate the inside and outside of the tube. By pressure-feeding air from an external pump (not shown), air is sent into the oil. The support section 7b is a member provided so as to contact the lower end of the filter panel 6 hanging downward from the chain 4 into the oil below, and keeps the filter panel 6 at an oblique angle. The filter panel 6 that descends on the rear side of the sprocket 5 and is immersed in the oil tends to hang vertically downward with its free end facing downward from the chain 4. At this time, the support section 7b positioned below the chain 4 contacts the free end of the filter panel 6 and supports the free end from below, so that the filter panel 6 maintains a posture at an oblique angle with respect to the vertical direction. With respect to this filter panel 6, the air sent out from the lower air supply section 7a physically contacts as bubbles, and thereby the solid particles collected on the surface of the filter panel 6 are peeled off. Here, since the filter panel 6 forms a non-vertical and oblique surface, the opportunity for the solid particles collected on the surface of the filter panel 6 to contact the bubbles increases, and the solid particles can be peeled off more efficiently. Incidentally, the cleaning performance by such a cleaning promotion device 7 will be verified in detail later.

[0028] In the filter unit 2, when the concentration of solid particles in the air to be purified is particularly high, etc., it is effective to adjust the rotational speed of the sprocket 5 to increase the feeding speed of the filter panel 6. However, if the feeding speed of the filter panel 6 is high, the residence time of the filter panel 6 in the liquid tank 3 will be shortened accordingly. During that time, if the filter panel 6 is simply immersed in oil, a situation where sufficient cleaning is not performed is also assumed. Under the situation where the feeding speed of the filter panel 6 must be increased, it is even more so because the amount of solid particles collected in each filter panel 6 is considered to be that much more. Also, assuming a situation where the air temperature is low, such as in winter, by immersing the filter panel 6 cooled by the air, the temperature of the oil also drops, the viscosity of the oil increases, and it is considered that it becomes difficult to wash off the solid particles adhering to the filter panel 6. Therefore, by providing the cleaning promotion device 7 as described above in the liquid tank 3, the filter panel 6 can be cleaned with high efficiency even in a short time or at a low temperature.

[0029] In addition, as the cleaning promotion device 7, instead of or in addition to the above-described bubble type device, for example, a stirring device that stirs the oil by a screw or a pump, an ultrasonic device that applies vibration to the oil, a heater that heats the oil, etc., devices with various principles and configurations may be provided. Also, a form such as providing a device similar to the heating unit 62 of the liquid treatment device 60 described later in the liquid tank 3 is also conceivable.

[0030] Note that FIG. 1 shows the case where only one continuous regeneration filter device 1 is installed in the dust removal device 100. However, the continuous regeneration filter device 1 may be provided with a plurality of units before and after, or left and right or up and down with respect to the air flow according to conditions such as the dust removal performance of the continuous regeneration filter device 1 and the required air flow rate.

[0031] Furthermore, in the present embodiment, a liquid treatment device 60 as shown in FIGS. 4 and 5 is connected to the continuous regeneration filter device 1. The liquid treatment device 60 is connected to the liquid tank 3 of the continuous regeneration filter device 1 and is a device that recovers the liquid (oil) mixed with solid particles stored in the liquid tank 3 and performs a process of separating and removing the solid particles from the oil.

[0032] The liquid treatment device 60 includes a sedimentation tank 61 for storing the oil mixed with solid particles recovered from the liquid tank 3, a heating unit 62 for heating the oil stored in the sedimentation tank 61, and a liquid recovery unit 63 for recovering the oil near the liquid surface among the oil stored in the sedimentation tank 61.

[0033] An inclination is provided at the lower part of the liquid tank 3 of the continuous regeneration filter device 1, and a draw-out pipe 3a is provided at the bottom. The outlet side of the draw-out pipe 3a is connected to the liquid treatment device 60, and a draw-out valve 3b for opening and closing the flow path in the draw-out pipe 3a is provided in the middle of the draw-out pipe 3a. The solid particles washed off from the filter panel 6 settle at the lower part of the liquid tank 3 and accumulate at the bottom along the inclination. When the draw-out valve 3b is opened at the stage where the solid particles have accumulated to a certain extent, the solid particles settled at the lower part of the liquid tank 3 are drawn out as sludge together with the oil from the draw-out pipe 3a and recovered by the liquid treatment device 60. Further, the inlet side of an overflow pipe 3c is connected to the storage upper limit level of the oil in the liquid tank 3. The outlet side of the overflow pipe 3c is connected to the sedimentation tank 61 of the liquid treatment device 60, and the oil exceeding the storage upper limit level in the liquid tank 3 flows into the sedimentation tank 61 through the overflow pipe 3c.

[0034] The sedimentation tank 61 is a device that stores the oil mixed with solid particles recovered as sludge from the liquid tank 3 and separates the solid particles and the oil by sedimentation treatment. An inclination is provided at the lower part of the sedimentation tank 61, and a discharge pipe 61a having a discharge valve 61b in the middle is connected to the bottom. When the discharge valve 61b is opened, the solid particles settled at the lower part of the sedimentation tank 61 are discharged as dust. The dust discharged from the sedimentation tank 61 through the discharge pipe 61a is recovered in a dust box 64.

[0035] As shown in FIG. 5, the sedimentation tank 61 is partitioned into two regions (referred to as an introduction section 61d and a sedimentation section 61e) in a plan view by a partition plate 61c extending in the vertical direction, and the outlet sides of the extraction pipe 3a and the overflow pipe 3c are connected to the introduction section 61d side. The partition plate 61c has its upper part exposed above the liquid level of the oil stored in the sedimentation tank 61, and its lower part extends below the liquid level but does not reach the bottom of the sedimentation tank 61. The introduction section 61d and the sedimentation section 61e communicate with each other at the lower part of the sedimentation tank 61. As a result, in the oil mixed with solid particles introduced from the extraction pipe 3a into the sedimentation tank 61, many particles with a specific gravity smaller than that of the oil and floating on the liquid surface stay on the surface of the introduction section 61d, while particles with a relatively large specific gravity sink into the liquid and flow into the sedimentation section 61e side together with the oil.

[0036] The introduction section 61d is further provided with a surface recovery net 61f and a surface recovery pipe 61g as a floating matter recovery section. As shown in FIGS. 4 and 5, the surface recovery net 61f is a thin metal net-like member provided along the liquid surface at a height near the liquid surface in the introduction section 61d of the sedimentation tank 61. Due to the above-described mechanism of providing the partition plate 61c to partition the sedimentation tank 61, a large amount of floating matter stays near the liquid surface in the introduction section 61d. One end of the surface recovery net 61f is rotatably attached around an axis in a direction along the horizontal direction with respect to the sedimentation tank 61, and it is configured to rotate between a standby posture in which at least a part of it is submerged below the liquid level and an operating posture in which the part submerged below the liquid level in the standby posture is lifted above the liquid level. Usually, the surface recovery net 61f is kept in the standby posture, and when the floating matter accumulates to a certain extent near the liquid surface of the introduction section 61d and the surface recovery net 61f is lifted to the operating posture, the floating matter is collected by the surface recovery net 61f.

[0037] Near the rotating shaft of the surface recovery net 61f, the inlet of the surface recovery pipe 61g is open, and the outlet side of the surface recovery pipe 61g is connected to the dust box 64. When the surface recovery net 61f is lifted to the operating position, the floating matter collected on its surface, together with the oil adhering to the surface recovery net 61f, flows along the surface recovery net 61f and into the surface recovery pipe 61g. In this way, it is possible to efficiently recover the floating matter, which is a solid with a small specific gravity and stays near the liquid level of the introduction part 61d, from the oil.

[0038] Also, the inlet of the surface recovery pipe 61g may be provided at the height of the upper limit of the liquid level in the sedimentation tank 61, and the surface recovery pipe 61g may be used as the overflow pipe of the sedimentation tank 61. In this case, when the oil stored in the sedimentation tank 61 overflows beyond the upper limit of the liquid level, the floating matter staying near the liquid level of the introduction part 61d flows into the surface recovery pipe 61g together with the oil, and thus it is also possible to recover the floating matter.

[0039] As the heating part 62, it is provided with a liquid level heater 62a provided above the liquid level of the sedimentation part 61e, and also includes a level sensor 62b for detecting the liquid level of the oil stored in the sedimentation tank 61 and a temperature sensor 62c for measuring the surface temperature of the oil. The liquid level detected by the level sensor 62b and the temperature of the oil measured by the temperature sensor 62c are input as sensor signals to a control device 70 (see FIG. 1) described later. The control device 70 controls the on / off and output of the liquid level heater 62a according to these sensor signals.

[0040] The liquid level heater 62a is, for example, an optical heater that irradiates the liquid level with near-infrared rays as heating light. The oil irradiated with the heating light absorbs the heating light and rises in temperature by its energy. Note that the wavelength of the irradiated light is not limited to near-infrared rays, and a wavelength suitable for heating the liquid assumed to be the heating target can be appropriately selected.

[0041] In the sedimentation tank 61, a collection liquid mixed with solid particles is stored, and the solid particles are separated by sedimentation treatment. However, when the collection liquid is, for example, oil, its viscosity varies greatly with temperature, and the lower the temperature, the higher the viscosity. Therefore, in the collection liquid stored in the sedimentation tank 61, the higher the temperature, the greater the sedimentation rate of the solid particles, and the lower the temperature, the smaller the sedimentation rate. Thus, in the liquid treatment apparatus 60 of this embodiment, the oil stored in the sedimentation tank 61 is heated by the heating unit 62 to promote the sedimentation of the solid particles.

[0042] Here, in the liquid treatment apparatus 60 of this embodiment, the oil is heated from the surface side (from above the liquid surface) rather than from the bottom. The purpose of heating is the sedimentation of solid particles. However, if heat is applied to the oil from the bottom, the entire region from the bottom to the liquid surface will be agitated by thermal convection, preventing the sedimentation of solid particles. If the oil is heated at the liquid surface, the temperature of the oil can be increased while suppressing the generation of thermal convection. In this case, of course, the temperature does not rise as much in the region deeper than near the surface. However, as will be described later, in this embodiment, the oil near the surface is recovered as the collection liquid from which the solid particles have been removed. Therefore, it is sufficient if sedimentation can be promoted in the region near the surface.

[0043] The temperature sensor 62c is, for example, a non-contact thermometer and is configured to measure the surface temperature of the oil that is the heating target of the liquid surface heater 62a. The control device 70 controls to turn on the operation of the liquid surface heater 62a or increase the output if the measured value of the temperature sensor is lower than the temperature of the oil suitable for the sedimentation of solid particles, and to turn off the operation of the liquid surface heater 62a or decrease the output if the measured value of the temperature sensor is higher than that.

[0044] Also, the heating efficiency of the oil by the liquid surface heater 62a, which is an optical heater, varies depending on the distance between the liquid surface heater 62a as the light source and the liquid surface of the target oil. Therefore, the control device 70 monitors the liquid level of the oil based on the sensor signal of the level sensor 62b. When turning on the liquid surface heater 62a to heat the oil, if the liquid level is high and the liquid surface is close to the upper liquid surface heater 62a, the output is lowered, and if the liquid level is low and far from the liquid surface heater 62a, the output is increased for control. In this way, by adjusting the output of the liquid surface heater 62a according to the distance between the liquid surface and the liquid surface heater 62a, more appropriate temperature adjustment becomes possible.

[0045] Note that the liquid surface heater 62a may be any heater that can heat the vicinity of the surface of the stored liquid without significant agitation. In addition to the optical heater, for example, a heater with a mechanism that immerses a heating element such as an electric heating wire in the liquid for heating may be adopted. However, considering that the liquid surface rises and falls depending on the storage volume, a heater with a principle and mechanism that facilitates heating on this premise is preferable. In this regard, the optical heater is suitable for the liquid surface heater 62a. Of course, for example, by moving the position of the heating element such as an electric heating wire following the level of the liquid surface, or by adjusting the amount of the stored liquid within a certain range while fixing the position of the heating element, the effect of heating only the region near the surface of the target liquid can also be obtained.

[0046] The same applies to the temperature sensor 62c. To measure the temperature of an object whose height changes, a non-contact temperature sensor is suitable. However, it is also possible to move a contact thermometer up and down according to the level of the liquid surface, adjust the level of the liquid surface within a certain range with respect to the measurement position of the thermometer, or provide a plurality of temperature sensors at different heights in the sedimentation tank 61 to measure the temperature at each level.

[0047] The liquid recovery section 63 is equipped with a suction nozzle 63a that sucks in the oil stored in the settling tank 61, and a recovery flow path 63b that recovers the oil sucked in from the suction nozzle 63a. The suction nozzle 63a is disposed in the settling section 61e of the settling tank 61, and is configured as a float nozzle that floats on the liquid surface by buoyancy and sucks in the liquid near the liquid surface. The inlet side of the recovery flow path 63b is connected to the suction nozzle 63a, and the outlet side is connected to the liquid tank 3 of the filter unit 2.

[0048] In the middle of the recovery flow passage 63b, a pump 63c for pumping the oil sucked from the suction nozzle 63a and a filter 63d for collecting solid particles contained in the oil are provided. The filter 63d is, for example, a double filter. In the settling tank 61, the introduction section 61d is partitioned as described above to remove suspended matter, and in the settling section 61e, solid particles near the surface are efficiently removed by a settling process using the liquid surface heater 62a or the like. For this reason, if the oil is collected near the liquid surface in the settling section 61e, most of the solid particles are removed and the oil that has been purified can be collected. In particular, if the oil is sucked from the suction nozzle 63a while being heated by the liquid surface heater 62a, the oil near the heated liquid surface can be collected, and the oil from which the solid particles have been removed can be efficiently collected. However, it is possible that some solid particles remain in the liquid because they cannot be completely removed, so the oil collected from the suction nozzle 63a is passed through the filter 63d to more reliably remove the solid particles.

[0049] In addition to the liquid tank 3 and the liquid treatment device 60, the dust removal device 100 of this embodiment is separately provided with a liquid tank 65 for storing clean oil that does not contain solid particles. In this embodiment, the collected liquid mixed with solid particles is treated by the liquid treatment device 60, and the collected liquid from which the solid particles have been removed is returned to the liquid tank 3. However, it is inevitable that the oil in the collected liquid decreases when discharging dust from the liquid treatment device 60. Therefore, a new collected liquid can be supplied from the liquid tank 65 to the liquid tank 3 as needed. Regarding the supply of the collected liquid, for example, a ball tap may be provided at the supply port from the liquid tank 65 to the liquid tank 3, and the supply port opens in response to a decrease in the liquid volume of the collected liquid in the liquid tank 3, so that an appropriate amount of the collected liquid is supplied to the liquid tank 3.

[0050] Mechanisms such as the liquid treatment device 60, the liquid tank 65, the dust box 64, and the extraction valve 3b provided in the extraction pipe 3a are installed outside the housing of the dust removal device 100 that forms the air flow path. When performing operations such as extracting sludge from the liquid tank 3, discharging dust from the liquid treatment device 60, treating the dust discharged into the dust box 64, cleaning and replacing the filter 63d, and replenishing oil to the liquid tank 65, it is possible to access these devices outside the dust removal device 100 and perform the necessary operations.

[0051] A post-filter chamber (tertiary dust removal chamber) 40 is provided downstream of the filter chamber 30, and the air that has passed through the continuous regeneration filter device 1 flows through here. Since the continuous regeneration filter device 1 captures solid particles in the air with oil as described above, the air that has passed through the continuous regeneration filter device 1 contains oil droplets peeled off from the filter panel 6 of the continuous regeneration filter device 1 and solid particles adhered with oil. The tertiary dust removal chamber 40 is a flow path provided so that these droplets and particles do not flow downstream as they are. Most of these droplets and particles fall and are removed from the air while the air flows through the tertiary dust removal chamber 40. In particular, since the particles adhered with oil have a larger mass and particle size, they can be efficiently removed by their own weight. The tertiary dust removal chamber 40 is, for example, a square duct provided horizontally, and the cross-sectional area and length of the duct are set so that the air velocity is appropriate for dust removal in the continuous regeneration filter device 1. In addition, as the shape and configuration of the tertiary dust removal chamber 40, other appropriate designs can be adopted. For example, it may have a bent shape or a structure such as a flow straightening plate.

[0052] Also, a dust monitor 41 is provided in the tertiary dust removal chamber 40 to monitor the concentration of solid particles in the air flowing through the tertiary dust removal chamber 40.

[0053] An outlet filter chamber 50 is provided downstream of the tertiary dust removal chamber 40. In the outlet filter chamber 50, a post-filter 51, which is, for example, a dry cartridge type filter device, is provided to further capture the particles contained in the air that has passed through the continuous regeneration filter device 1 and then through the tertiary dust removal chamber 40, and supply the purified air to the downstream equipment 200. The outlet filter chamber 50 is designed to allow people to enter, and the post-filter 51 can be cleaned or replaced as needed.

[0054] The operation of the above-described dust collector 100 is controlled by a control device 70. The control device 70 is a device that monitors and controls the status of each part constituting the dust collector 100. Based on the required air flow rate in the facility 200 and the concentration of particles in the air obtained from the dust monitor 41, it adjusts the feed speed of the filter panel 6 in the continuous regeneration filter device 1 (the rotation speed of the sprocket 5), the damper opening degree in the flow rate adjustment unit 21, the output of the liquid surface heater 62a in the heating unit 62, and the like.

[0055] Thus, in the dust collector 100 of this embodiment, a wet continuous regeneration filter device 1 that captures particles in the air with a filter panel 6 immersed in oil is used, and high purification performance is exhibited even under high-load conditions such as purifying air containing volcanic ash. The filter panel 6 is immersed in the oil stored in the liquid tank 3, and the collected solid particles are washed off to regenerate the collection layer while being continuously sent to the air flow path. Therefore, the continuous regeneration filter device 1 and the dust collector 100 can be continuously operated while maintaining the collection performance. Further, a cleaning promotion device 7 is provided in the liquid tank 3, and the solid particles collected on the filter panel 6 are efficiently washed off by the cleaning promotion device 7, and the filter panel 6 is regenerated. Therefore, the collection performance can be suitably maintained even in a situation where the feed speed of the filter panel 6 needs to be increased to increase the amount of solid particles collected.

[0056] In addition, a liquid treatment device 60 and a liquid tank 65 are connected to the liquid tank 3. Solid particles washed off from the filter panel 6 and accumulated in the liquid tank 3 are appropriately recovered, and clean oil is supplied as needed. Therefore, a situation where solid particles accumulate too much in the liquid tank 3 and the collection performance of the filter panel 6 cannot be sufficiently regenerated is avoided, and the operation of the dust removal device 100 can be continued while maintaining a high collection performance by the continuous regeneration filter device 1 for a long time. The liquid tank 3 provided in the continuous regeneration filter device 1 itself can store a certain amount of solid particles collected by the filter panel 6, and thus the filter panel 6 can be continuously regenerated for a certain period of time. However, for example, during a volcanic eruption, it is also assumed that there may be a case where a large amount of dust needs to be continuously processed over a long period of time. Under such high-load conditions, relying only on the storage capacity of the liquid tank 3, the regeneration ability of the filter panel 6 by the liquid tank 3 may reach its limit in a short period. Therefore, as in the present invention, in addition to the liquid tank 3, a liquid treatment device 60 is further provided. By treating the oil in the liquid tank 3, the filter panel 6 can be regenerated over a long period, and the dust removal ability of the filter panel 6 can be continuously maintained.

[0057] In addition, in the liquid treatment device 60, when removing solid particles by precipitation treatment, there is a problem that rapid precipitation does not occur when the temperature of the oil is low. However, in this embodiment, by heating the oil from the surface, the viscosity of the oil near the surface is reduced without causing intense agitation due to thermal convection, promoting the precipitation of solid particles, and further recovering and reusing the oil near the surface. Thereby, the removal of solid particles using precipitation treatment can be efficiently performed.

[0058] In addition, since the liquid treatment device 60 and its peripheral mechanisms can be accessed outside the air flow path in the dust removal device 100, when the accumulation amount of the treated oil and removed solid particles in the liquid treatment device 60 increases, or when the amount of oil supplied to the liquid tank 3 decreases, while continuing the operation of the dust removal device 100, it is possible to access each device outside and perform operations such as removing the treated oil and solid particles and replenishing clean oil.

[0059] An experimental verification of the cleaning promotion function of the filter panel 6 by the above-described cleaning promotion device 7 will be described. The experiment was conducted according to the following procedure. First, one filter panel 6 was immersed in oil, which is the collection liquid, and then lifted, left standing for 15 minutes to let the oil drip off, and then the mass was measured. This mass was regarded as the mass when the cleaning rate was 100%. This mass is the mass of the filter panel 6 in a state where an oil film as a collection layer is formed on the surface but no solid particles are collected.

[0060] Next, the same filter panel 6 was immersed in oil, which is the collection liquid, and a certain amount (for example, 3 grams) of solid particles was attached thereto. The solid particles are, for example, a mixed dust obtained by mixing volcanic ash of various particle sizes. Then, it was left standing for 5 minutes, and the mass of the filter panel 6 was measured in a state where the solid particles were impregnated with oil and made to conform. This mass was regarded as the mass when the cleaning rate was 0%. This mass is the mass of the filter panel 6 in a state where an oil film as a collection layer is formed on the surface and solid particles are further collected thereon, and is larger than the mass when the cleaning rate is 100%.

[0061] The filter panel 6 in the state with a cleaning rate of 0% to which solid particles were attached was immersed in an experimental tank in which oil, which is the collection liquid, was stored for a certain period of time, then lifted from the experimental tank and left standing, and the mass was measured periodically to observe the change in mass. Linear interpolation was performed between the mass when the cleaning rate was 0% and the corresponding cleaning rate (0%), and the mass when the cleaning rate was 100% and the corresponding cleaning rate (100%), and the cleaning rate corresponding to the measured mass value was calculated.

[0062] As shown in Fig. 7, the experimental tank is configured to store oil, which is the collection liquid, and to accommodate one filter panel 6 in a manner that it is immersed therein, and it has a mechanism corresponding to the air supply part 7a and the support part 7b of the cleaning promotion device 7 in Fig. 4 inside. As shown in Fig. 7, the air supply part 7a is configured as a total of three air supply pipes, and 19 air supply holes with a diameter of 0.5 mm are respectively opened at equal intervals on the upper surface of each air supply pipe. The air supply part 7a and the support part 7b can be changed in position within the experimental tank and removed from the experimental tank. Also, although not shown in the figure, the entire experimental tank is accommodated in a thermostat so that the temperature of the entire experimental system can be adjusted.

[0063] The experiment was carried out while appropriately changing conditions such as the oil temperature, the distance from the air supply part 7a to the lower end of the filter panel 6, the angle of the filter panel 6 supported by the support part 7b, and the cleaning time.

[0064] The results are shown in the graphs of Figs. 8 and 9. Fig. 8 shows the results of verifying the difference in cleaning efficiency depending on the presence or absence of air supply by the air supply part 7a. The dashed-dotted line indicates the case where no air supply was performed, and the solid line indicates the case where air supply was performed. In the cleaning process, in both cases, the filter panel 6 was held at an angle of 60° with respect to the vertical direction. The cleaning time (the time for immersing the filter panel 6 in the oil) was set to three cases: 5 minutes, 10 minutes, and 15 minutes. After pulling up the filter panel 6 from the oil, the change in mass was observed over 180 minutes and shown in the graph as the cleaning rate. When performing cleaning, air supply was carried out from a position 60 mm below the lower end of the filter panel 6, and the air supply volume was 0.25 L / min per air supply hole. In Fig. 8, (A) shows the case where the oil temperature is 0°C, and (B) shows the case where the oil temperature is 25°C.

[0065] First, when the oil temperature is 25°C (see Figure 8(B)), at the 5-minute mark after lifting, in the group where air was not supplied, the cleaning rate was 30% - 40%. As the oil dropped and the mass decreased from then on, at the 15-minute mark, the cleaning rate became 50 - 60%. After 60 minutes, the increase in the cleaning rate (the amount of oil dropping per hour) slowed down, and the cleaning rate at the 180-minute mark remained in the range of around 60% - 70%. In contrast, in the group where air was supplied, at the 5-minute mark after lifting, the cleaning rate was 40 - 60%, and finally reached around 80%. It should be noted that in the group where air was supplied, it was observed that the cleaning rate was higher when the cleaning time was shorter compared to when it was longer. However, this is thought to be due to errors caused by the experimental operation.

[0066] When the oil temperature was 0°C (see Figure 8(A)), since the viscosity of the oil was high, the overall cleaning rate was low. In the group where air was not supplied, the cleaning rate at the 5-minute mark after lifting was less than 20%, and remained at around 50% - 60% after 60 minutes. The cleaning rate in the group where air was supplied was higher than that. At the 5-minute mark after lifting, it was 20% - 30%, and reached around 70% after 60 minutes.

[0067] Thus, in both the case of an oil temperature of 0°C and 25°C, the cleaning rate of the group where air was supplied was significantly higher than that of the group where air was not supplied. Regarding the cleaning of the filter panel 6 by immersion in oil, the promotion of the cleaning effect by air supply was recognized.

[0068] Subsequently, an examination was conducted on the conditions regarding the angle of the filter panel 6 and the distance of the air supply part 7a from the filter panel 6 when air was supplied. The results are shown in Figure 9.

[0069] In Fig. 9, (A) and (B) show the results when the air supply part 7a is arranged downward at a distance of 20 mm from the lower end of the filter panel 6, and (C) and (D) show the results when the distance between the lower end of the filter panel 6 and the air supply part 7a is 60 mm. In (A) and (C), the oil temperature is 0°C, and in (B) and (D), the oil temperature is 25°C. For each condition, further verification was carried out regarding the support angle of the filter panel 6 in three ways: 45°, 60°, and 75° with respect to the vertical direction. Bubbles sent out from the lower air supply part 7a come into contact with the lower surface of the obliquely supported filter panel 6 and escape upward. In each figure, the horizontal axis represents the support angle of the filter panel 6 with respect to the vertical direction, the vertical axis represents the cleaning rate, and each point shows the cleaning rate at 5 minutes, 15 minutes, and 30 minutes after the filter panel 6 is lifted out of the oil.

[0070] First, considering the distance between the filter panel 6 and the air supply section 7a, the cleaning rate at the 15-minute point after lifting is slightly less than 50% - 60% at (A) (oil temperature 0°C, distance 20 mm), while it is slightly more than 50% - slightly more than 60% at (C) (oil temperature 0°C, distance 60 mm). Also, the cleaning rate at the 15-minute point after lifting is slightly less than 40% - slightly less than 50% at (B) (oil temperature 25°C, distance 20 mm), while it is around 50% at (D) (oil temperature 25°C, distance 60 mm). That is, it can be said that it is preferable to arrange the air supply section 7a below the filter panel 6 with a certain interval. This is because in cleaning by air supply, it can promote cleaning if bubbles contact the surface of the filter panel 6 as evenly as possible. However, if the distance from the air supply section 7a, which is the bubble ejection nozzle, to the filter panel 6 is too short, the ejected bubbles do not grow large and contact the filter panel 6 in a state where the distribution in the liquid is uneven. As a result, the area of the surface of the filter panel 6 that contacts the bubbles is limited to a part. On the other hand, if the distance between the air supply section 7a and the filter panel 6 is too large, the bubbles widely dissipate in the oil, and only a limited number of bubbles can contact the filter panel 6. In addition, it also affects the layout in the limited space in the liquid tank 3 (see Fig. 4). Therefore, the distance should not be made too large. From the above, the distance from the air supply section 7a to the lower end of the filter panel 6 depends on various conditions such as the flow rate of the gas to be fed and the shape of the filter panel 6. For example, it is preferably set to 30 mm or more and 120 mm or less, more preferably around 40 mm or more and 80 mm or less. Since the state of convection in the liquid tank changes depending on the air supply volume, oil temperature, number and arrangement of air supply holes in the air supply section 7a, etc., in an actual machine, the distance from the filter panel 6 should be set considering such effects.

[0071] Next, considering the angle of the filter panel 6, at (A) (oil temperature 0°C, distance from the air supply section 7a: 20 mm), the cleaning rate is the highest at 60° among 45°, 60°, and 75°. At (B) (oil temperature 25°C, distance: 20 mm), the cleaning rate increases in the order of 45°, 60°, and 75°. Also, at (C) (oil temperature 0°C, distance: 60 mm), the cleaning rate increases in the order of 45°, 60°, and 75°. At (D) (oil temperature 25°C, distance: 60 mm), the cleaning rate is about the same at any angle. Overall, when performing cleaning by air supply, the cleaning efficiency is higher when the filter panel 6 is inclined to some extent with respect to the vertical direction. As far as the results of this verification experiment are concerned, it can be said that it is particularly preferable to set it around 60°.

[0072] This is considered to be due to the following mechanism. When the angle of the filter panel 6 is vertical or close to vertical, the bubbles supplied from below quickly flow upward along the direction of the filter panel 6, and the contact opportunity of the bubbles with the surface of the filter panel 6 is small. If the inclination angle of the filter panel 6 with respect to the vertical direction is larger than that, the bubbles that collide with the filter panel 6 from below move along the surface of the filter panel 6 and then rise, or stay on the surface of the filter panel 6 on the way. When the bubbles move along the surface of the filter panel 6, the speed becomes slower as the inclination angle of the filter panel 6 with respect to the vertical direction becomes larger. As a result, the contact time of the bubbles on the surface of the filter panel 6 becomes longer, and the cleaning efficiency is improved.

[0073] On one hand, since the filter panel 6 having a structure in which louvers are passed to a frame has holes penetrating through its front and back, when the inclination of the filter panel 6 is increased, it becomes easier for the bubbles trying to move upward to pass through the holes. For the greatly inclined filter panel 6, the bubbles passing through the holes either do not contact the filter panel 6 or, even if they do, the contact is for a short time. Therefore, if the inclination angle of the filter panel 6 is increased too much, conversely, the contact opportunity between the bubbles and the filter panel 6 decreases, and the cleaning efficiency may drop. From the above, the angle of the filter panel 6 depends on the dimensions and shape of the filter panel 6, the configuration of the air supply part 7a, and the arrangement with respect to the filter panel 6. For example, it is preferably set to be 45° or more and 80° or less, more preferably about 55° or more and 75° or less with respect to the vertical direction. In particular, when the oil temperature is low, it is effective to set the inclination angle to be larger. Specifically, although it also depends on the composition of the oil, etc., for example, when the oil temperature is 10°C or more, the inclination angle of the filter panel 6 is in the range of 45° or more and 65° or less, and when the oil temperature is less than 10°C, the inclination angle is in the range of 60° or more and 80° or less. Such adjustments may be made. Also, in order to be able to change the inclination angle of the filter panel 6 according to the oil temperature, for example, it is also conceivable to configure the position of the support part 7b in the cleaning promotion device 7 to be adjustable. In this way, if the cleaning promotion device 7 is provided with the support part 7b and the filter panel 6 is supported at an appropriate angle, the bubbles contact the filter panel 6 at an oblique angle, and the cleaning by air supply can be performed more efficiently.

[0074] As described above, the dust removal device 100 of the above embodiment forms a collection layer by a collection liquid on the surface, and includes a wet filter panel 6 that is sent into the air flow path to collect solid particles in the air, a liquid tank 3 that stores the collection liquid and immerses the filter panel 6 in the collection liquid, and a cleaning promotion device 7 that has an air supply part 7a for sending gas from below to the filter panel 6 immersed in the collection liquid in the liquid tank 3. In this way, regarding the cleaning of the filter panel 6 by immersion in the collection liquid, the cleaning effect can be enhanced by air supply.

[0075] In the dust collector 100 of this embodiment, the cleaning promotion device 7 further includes a support portion 7b that supports the filter panel 6 immersed in the liquid tank 3 at an oblique angle. In this way, by the bubbles coming into contact with the filter panel 6 supported at an oblique angle, cleaning by air supply can be performed more efficiently.

[0076] The dust collector 100 of this embodiment includes a liquid treatment device 60 that separates solid particles from the collected liquid mixed with solid particles drawn out from the liquid tank 3, and is configured such that the collected liquid from which the solid particles have been separated can be returned from the liquid treatment device 60 to the liquid tank 3. In this way, the filter panel 6 can be regenerated over a long period of time, and the dust removal ability of the filter panel 6 can be continuously maintained.

[0077] Therefore, according to the above-described embodiment, suitable dust removal performance can be maintained for a long time.

[0078] Note that the dust collector of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0079] 3 Liquid tank 6 Filter panel 7 Cleaning promotion device 7a Air supply portion 7b Support portion 100 Dust collector

Claims

1. A wet filter panel having a collection layer formed by a collection liquid on its surface and sent through an air flow path to collect solid particles in the air, a liquid tank for storing the collection liquid and immersing the filter panel in the collection liquid, and a cleaning promotion device provided with an air supply unit for sending gas from below to the filter panel immersed in the collection liquid in the liquid tank characterized by comprising a dust removal device.

2. The cleaning promotion device further comprises a support portion for supporting the filter panel immersed in the liquid tank at an oblique angle characterized by the dust removal device according to Claim 1.

3. It is provided with a liquid treatment device for separating solid particles from the collection liquid mixed with solid particles drawn out from the liquid tank, and is configured such that the collection liquid from which the solid particles have been separated can be returned from the liquid treatment device to the liquid tank characterized by the dust removal device according to Claim 1.

Images