Method and apparatus for separating solid in liquid

Abstract

To provide a method and an apparatus for separating a solid in liquid which can simply and suitably carry out sedimentation treatment, when separating liquid and solid particles by the sedimentation treatment.SOLUTION: A separation apparatus 60 includes a sedimentation tank 61 for storing liquid mixed with solid particles, and a liquid level heater 62a for heating the liquid level of the liquid stored in the sedimentation tank 61. The liquid level heater 62a is used as an optical heater for emitting heating light, and adjusts output of the liquid level heater 62a according to a measured value of a level sensor 62b.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for separating solid particles from a liquid mixed with solid particles.

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] As prior art documents related to this type of dust removal device, for example, there is the following Patent Document 1. In the collision adhesion type air purification device described in Patent Document 1 below, a panel made of a metal material is immersed in oil to form an oil film on the surface, and air is made to collide here to collect solid particles contained in the air. The panel constituting the filter is immersed in oil again after collecting the solid particles, whereby the collected solid particles are washed away and the oil film on the surface is regenerated.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the apparatus as described in the above Patent Document 1, solid particles collected on the panel accumulate in the oil tank during operation, so it is necessary to remove them. The removal of solid particles may be performed, for example, by manually scraping out the solid particles from the oil tank using a scraper or the like, but it is also possible to draw out the oil-mixed solid particles from the bottom of the oil tank. Further, for example, when considering separating and reusing the oil therefrom, the oil-mixed solid particles drawn out from the oil tank are stored in a sedimentation tank and subjected to sedimentation treatment, and the supernatant from which the solid particles have been separated can be used as recycled oil.

[0006] Here, depending on the environment and season of the place where solid particles in the air are collected or sedimentation treatment of oil mixed with solid particles is performed, it can be assumed that the temperature of the oil to be subjected to sedimentation treatment is low. For most oils, the lower the temperature, the higher the viscosity, and the higher the viscosity, the slower the sedimentation rate of solid particles and the longer it takes for sedimentation treatment.

[0007] Assuming a state where the sedimentation rate of solid particles is slow, as a measure to ensure the necessary sedimentation treatment capacity, it is conceivable to increase the scale of the sedimentation tank, but it is necessary to increase the scale of the equipment, and depending on the conditions, it is not realistic in terms of installation area, volume, and installation cost.

[0008] In view of such circumstances, the present invention aims to provide a method and apparatus for separating solid matter in liquid that can perform sedimentation treatment simply and suitably when separating a liquid and solid particles by sedimentation treatment.

Means for Solving the Problems

[0009] The present invention relates to a method for separating solid matter in liquid, characterized in that, for a sedimentation tank storing a liquid mixed with solid particles, the sedimentation of solid particles near the liquid surface is promoted by heating the liquid surface of the stored liquid.

[0010] In the method for separating solid matter in liquid of the present invention, among the liquid stored in the sedimentation tank, the heated liquid near the liquid surface can be recovered as the liquid from which solid particles have been removed.

[0011] In the method for separating solid matter in liquid of the present invention, as a liquid surface heater for heating the liquid surface of the liquid stored in the sedimentation tank, an optical heater that irradiates heating light is used, and the output of the liquid surface heater can also be adjusted according to the distance between the liquid surface heater and the liquid surface.

[0012] The present invention also relates to a device for separating solid matter in liquid, which includes a sedimentation tank for storing a liquid mixed with solid particles and a liquid surface heater for heating the surface of the liquid stored in the sedimentation tank.

[0013] In the device for separating solid matter in liquid of the present invention, the liquid surface heater can be an optical heater that irradiates heating light.

[0014] The device for separating solid matter in liquid of the present invention can be configured to include a level sensor for measuring the liquid level of the liquid stored in the sedimentation tank, and to adjust the output of the liquid surface heater according to the measurement value of the level sensor.

[0015] The device for separating solid matter in liquid of the present invention can also be provided with a liquid recovery section for recovering the heated liquid near the liquid surface from the liquid stored in the sedimentation tank.

Advantages of the Invention

[0016] According to the method and device for separating solid matter in liquid of the present invention, when separating liquid and solid particles by sedimentation treatment, excellent effects of performing the sedimentation treatment simply and suitably can be achieved.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0019] FIG. 1 shows an example of the form of a dust removal device as an application target of the solid-in-liquid separation device 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 forming 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 solid-in-liquid separation device (hereinafter simply referred to as the "separation device") 60 for recovering the oil after adsorbing solid particles in the air in the continuous regeneration filter device 1, separating the solid particles, and re-supplying them 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 suction of air in the facility 200 (for example, a gas turbine generator inhales a large amount of air during operation), but a fan or the like for assisting the air circulation may be provided as necessary.

[0020] 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 the weight exceeds the force trying to rise due to the 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 the buoyancy force 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 duct, an inlet may be provided at the top and an outlet may be provided at the bottom. Alternatively, for the purpose of performing dust removal by colliding the air with the inner wall or adjusting the air flow velocity by the 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 collide the air and remove solid particles or to adjust the air flow velocity, direction, etc.

[0021] 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 is a part that plays a role in 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. The duct shape, length, cross-sectional area, etc. are appropriately designed so that an appropriate amount of air can flow through. Also, a structure such as a straightening plate or a throttle may be provided as necessary.

[0022] Near the entrance inside the secondary dust removal chamber 20, a flow velocity adjustment unit 21 for further adjusting the flow velocity of air is provided. The flow velocity 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 flow velocity of the air. Specifically, the higher the flow velocity of the air, 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, the dust removal amount of the continuous regeneration filter device 1 can be adjusted by the feeding speed of the filter in the continuous regeneration filter device 1 as described later. Therefore, while adjusting the feeding speed of the filter in the continuous regeneration filter device 1, the flow velocity of the air is adjusted by the flow velocity adjustment unit 21, so that the flow velocity of the air is adjusted to a speed suitable for the continuous regeneration filter device 1 to maintain the cleanliness of the air, and an amount of air required for the equipment 200 can be supplied.

[0023] A continuous regeneration filter device 1 is provided in the filter chamber 30. The continuous regeneration filter device 1 in this embodiment is the same device as the collision adhesion type air purification device described in the above Patent Document 3, and is configured to include a filter unit 2 and a liquid tank 3 as shown in FIGS. 2 and 3.

[0024] 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.

[0025] 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.

[0026] The filter panel 6 is a metal member in the shape of a rectangular frame with a plurality of louvers passed through it as shown in FIG. 6, for example. During the operation of the continuous playback filter device 1, the air flow flows in a direction orthogonal to the plane along the vertical direction formed by a large number of filter panels 6. For 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 purification can be performed 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 as a whole, thereby ensuring the surface area and improving the collection efficiency.

[0027] 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.

[0028] Therefore, in the continuous regeneration filter device 1 of this 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.

[0029] 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 rotating 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 with respect to 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 moves 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, during one revolution around the sprocket 5, both the front and back surfaces of the filter panel 6 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.

[0030] 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 oil adheres again, renewing the oil film forming the collection layer on the surface. Thus, the filter panel 6 continuously circulates while being continuously sent to the air flow path, passing through the oil in the liquid tank 3 in the middle of the path, and continuously regenerating the collection performance of solid particles with the oil. 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.

[0031] 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.

[0032] Also, 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.

[0033] As shown in FIG. 4, the cleaning promotion device 7 includes an air supply unit 7a that sends gas (air) into the oil stored in the liquid tank 3, and a support unit 7b that supports the filter panel 6 immersed in the oil at an appropriate angle. The air supply unit 7a is, for example, a tube through which air passes and a ventilation pipe having holes that communicate the inside and outside of the tube. By pressure-feeding air from an external pump (not shown), the air is sent into the oil. The support unit 7b is a member provided so as to contact the lower end of the filter panel 6 hanging down from the chain 4 into the lower oil, 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 the free end facing downward from the chain 4. At this time, the support unit 7b located 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. The air sent out from the lower air supply unit 7a physically contacts the filter panel 6 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 chance of the solid particles collected on the surface of the filter panel 6 coming into contact with the bubbles increases, and the solid particles can be peeled off more efficiently.

[0034] 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, just immersing the filter panel 6 in oil may not result in sufficient cleaning. Under circumstances where the feeding speed of the filter panel 6 must be increased, it is even more so because the amount of solid particles collected on each filter panel 6 is considered to be correspondingly large. Also, assuming a situation where the air temperature is low, such as in winter, immersing the filter panel 6 cooled by the air will lower the temperature of the oil, increasing the viscosity of the oil and making it 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.

[0035] 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 configuration such as providing a device similar to the heating unit 62 of the separation device 60 described later in the liquid tank 3 is also conceivable.

[0036] Note that FIG. 1 illustrates 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.

[0037] Furthermore, in this embodiment, a separation device 60 as shown in FIGS. 4 and 5 is connected to the continuous regeneration filter device 1. The separation device 60 is a device that is connected to the liquid tank 3 of the continuous regeneration filter device 1, collects 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.

[0038] The separation device 60 includes a sedimentation tank 61 that stores the oil mixed with solid particles recovered from the liquid tank 3, a heating unit 62 that heats the oil stored in the sedimentation tank 61, and a liquid recovery unit 63 that recovers the oil near the liquid surface among the oil stored in the sedimentation tank 61.

[0039] An inclination is provided at the lower part of the liquid tank 3 of the continuous regeneration filter device 1, and a draw-off pipe 3a is provided at the bottom. The outlet side of the draw-off pipe 3a is connected to the separation device 60, and a draw-off valve 3b for opening and closing the flow path in the draw-off pipe 3a is provided in the middle of the draw-off 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-off 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-off pipe 3a and recovered by the separation device 60. In addition, 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 separation 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.

[0040] 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 provided with 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.

[0041] As shown in Fig. 5, the sedimentation tank 61 is partitioned into two regions (referred to as the introduction section 61d and the 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. Thus, 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.

[0042] 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 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.

[0043] Near the rotation axis 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 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 staying near the liquid level of the introduction part 61d, from the oil.

[0044] 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.

[0045] As the heating part 62, it includes a liquid level heater 62a provided above the liquid level of the sedimentation part 61e, 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.

[0046] The liquid level heater 62a is, for example, an optical heater that irradiates near-infrared rays as heating light to the liquid level. The oil irradiated with the heating light absorbs the heating light and its temperature rises due to the 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.

[0047] 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 depending on the 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 separation device 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.

[0048] Here, in the separation device 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. By heating the oil 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 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.

[0049] 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 the 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.

[0050] In addition, 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 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 grasped as the measured value of the level sensor 62b and the liquid surface heater 62a, more appropriate temperature adjustment becomes possible. The function of the liquid-solid matter in the sedimentation tank 61 using such a liquid surface heater 62a will be verified in detail later.

[0051] The procedure for the separation process of the liquid-solid matter as described above using the separation device 60 equipped with the liquid surface heater 62a can be summarized in a flowchart as shown in FIG. 7, for example.

[0052] The procedure regarding the operation of the heating unit 62 is as follows, for example. First, regarding the oil mixed with solids stored in the sedimentation tank 61, the liquid level is first measured with the level sensor 62b (step S1). When the liquid level is within the range of values set as the condition for performing the heating process of the oil in the sedimentation process (for example, equal to or higher than a predetermined threshold value), the temperature of the oil is further measured with the temperature sensor 62c (step S2). When the temperature sensor 62c is a non-contact type temperature sensor, the temperature of the liquid surface is measured.

[0053] If the measured temperature of the oil is equal to or higher than the predetermined threshold value, the process returns to step S1. However, if the temperature is lower than the threshold value, the process proceeds to step S3, and the liquid surface heater 62a is turned on to heat the oil. At that time, the output of the liquid surface heater 62a is adjusted according to the liquid level measured by the level sensor 62b and the current temperature of the oil measured by the temperature sensor 62c.

[0054] During heating, the temperature is continuously monitored by the temperature sensor 62c (step S4). When the temperature reaches or exceeds a predetermined threshold, the operation of the liquid surface heater 62a is turned off and the heating is terminated (step S6). The threshold used for the determination in step S4 is set higher than, for example, the threshold used for the determination in step S2.

[0055] Also, during heating, the liquid level is continuously monitored by the level sensor 62b (step S5). Even if the temperature is less than the threshold in step S4, if it is determined in step S5 that the liquid level is outside the numerical range for performing the heat treatment, the heating is terminated (step S6). The setting of the numerical value used for the determination in step S5 may be the same as the setting of the numerical value in step S1, or different numerical values may be set.

[0056] After turning off the liquid surface heater 62a in step S6, the process returns to step S1.

[0057] On the other hand, the procedure regarding the operation of the liquid recovery unit 63 is as follows, for example. First, the liquid level is measured by the level sensor 62b (step S7). When the liquid level is within the range of the numerical values set as the conditions for performing oil recovery (for example, equal to or higher than a predetermined threshold), the temperature of the oil is further measured by the temperature sensor 62c (step S8).

[0058] If the measured temperature of the oil is less than the predetermined threshold, the process returns to step S7. If the temperature is equal to or higher than the threshold, it is further determined how long the state where the temperature is equal to or higher than the predetermined threshold has continued up to the current time (how many times the determination in step S8 was "equal to or higher than the threshold" has been repeated continuously up to the current time) (step S9). When the duration of the state where the oil temperature is equal to or higher than the predetermined threshold is equal to or longer than the predetermined threshold, the process proceeds to step S10 and the oil is recovered (circulated and reused to the liquid tank 3).

[0059] Here, the numerical setting of the liquid level used for the determination in step S7 may be the same as any one of the numerical settings used in step S1 or step S5, or different numerical values may be set. Further, the threshold value related to the temperature used for the determination in steps S8 and S9 is set to be the same as or lower than the threshold value used for the determination in step S2, for example.

[0060] In step S10, the pump 63c of the liquid recovery unit 63 is operated to suck the supernatant oil near the liquid level from the suction nozzle 63a. The solid particles remaining even after the treatment in the sedimentation tank 61 are removed when passing through the filter 63d, and the thus purified clean oil is returned from the outlet side of the recovery flow path 63b to the liquid tank 3.

[0061] During the execution of oil recovery, the monitoring of the liquid level and temperature is continued (steps S11, S12). When the liquid level becomes less than a predetermined threshold value or the temperature of the oil becomes less than a predetermined threshold value, the pump 63c is stopped and the reuse of the oil is terminated (step S13). After step S13, the process returns to step S7, and if the state of the oil satisfies the conditions again, the oil recovery (step S10) is restarted. Note that the threshold value related to the liquid level used for the determination in step S11 may be set to be the same as or lower than the threshold value used in step S7, for example. Also, for the threshold value related to the temperature used for the determination in step S12, it may be set to be the same as or lower than the threshold value used in step S8, for example. Note that in a series of steps related to oil recovery, when returning the oil to the liquid tank 3, the liquid level in the liquid tank 3 may be considered as a condition (illustration in the flowchart is omitted).

[0062] As for the liquid surface heater 62a, any heater that can heat the vicinity of the surface of the stored liquid without significant agitation may be used. In addition to optical heaters, for example, a heater with a mechanism that immerses a heating element such as a heating wire in the liquid for heating may be employed. However, considering that the liquid level fluctuates depending on the storage volume, a heater with a principle and mechanism that facilitates heating on this premise is preferable. In this regard, an optical heater is suitable for the liquid surface heater 62a. Of course, for example, by moving the position of a heating element such as a 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.

[0063] The same applies to the temperature sensor 62c. For measuring the temperature of an object whose height fluctuates, 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.

[0064] The liquid recovery section 63 includes a suction nozzle 63a that sucks the oil stored in the sedimentation tank 61, and a recovery flow path 63b that recovers the oil sucked from the suction nozzle 63a. The suction nozzle 63a is arranged in the sedimentation section 61e of the sedimentation tank 61 and is configured as a float nozzle that floats on the liquid surface by buoyancy and sucks the liquid near the liquid surface. The recovery flow path 63b has an inlet connected to the suction nozzle 63a and an outlet connected to the liquid tank 3 of the filter unit 2.

[0065] 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.

[0066] In addition to the liquid tank 3 and the separator 60, the dust remover 100 of this embodiment is provided with a liquid tank 65 for storing clean oil that does not contain solid particles. In this embodiment, the collected liquid containing solid particles is treated by the separator 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 will decrease when the dust is discharged from the separator 60. Therefore, new collected liquid can be supplied from the liquid tank 65 to the liquid tank 3 as necessary. Regarding the supply of 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 may open as the amount of collected liquid in the liquid tank 3 decreases, so that an appropriate amount of collected liquid can be supplied to the liquid tank 3.

[0067] Mechanisms such as the separation 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 sludge extraction from the liquid tank 3, dust discharge from the separation device 60, treatment of the dust discharged into the dust box 64, cleaning and replacement of the filter 63d, and oil replenishment to the liquid tank 65, access to these devices can be obtained outside the dust removal device 100 to perform the necessary operations.

[0068] A post-filter chamber (tertiary dust removal chamber) 40 is provided at the rear stage of the filter chamber 30, and the air that has passed through the continuous regeneration filter device 1 circulates 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 attached 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 attached 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 flow velocity is suitable 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 also be adopted. For example, it may have a bent shape or a structure such as a flow rectifying plate.

[0069] In addition, 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.

[0070] A downstream section of the third dust removal chamber 40 is provided with an outlet filter chamber 50. The outlet filter chamber 50 is provided with a post-filter 51 which is, for example, a dry cartridge type filter device. The post-filter 51 further captures particles contained in the air that has passed through the continuous regeneration filter device 1 and further through the third dust removal chamber 40, and supplies 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.

[0071] The operation of the above-described dust removal device 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 removal device 100. Based on the air flow rate required in the equipment 200 and the concentration of particles in the air obtained from the dust monitor 41, the feed speed of the filter panel 6 (the rotation speed of the sprocket 5) in the continuous regeneration filter device 1, the damper opening in the flow rate adjustment unit 21, the output of the liquid surface heater 62a in the heating unit 62, etc. are adjusted.

[0072] In this way, in the dust removal device 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, so that the continuous regeneration filter device 1 and the dust removal device 100 can be continuously operated while maintaining the collection performance. Furthermore, 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 has to be increased to increase the amount of solid particles collected.

[0073] In addition, a separation device 60 and a liquid tank 65 are connected to the liquid tank 3. The 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 can store the solid particles collected by the filter panel 6 to a certain extent by itself, 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 are cases 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, there is a risk that the regeneration ability of the filter panel 6 by the liquid tank 3 will reach its limit in a short period of time. Therefore, as in the present invention, in addition to the liquid tank 3, a separation 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 of time, and the dust removal ability of the filter panel 6 can be continuously maintained.

[0074] In addition, in the separation device 60, when removing solid particles by sedimentation treatment, there is a problem that rapid sedimentation 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 heat convection, promoting the sedimentation of solid particles, and further recovering and reusing the oil near the surface. Thereby, the removal of solid particles using sedimentation treatment can be efficiently performed.

[0075] In addition, since the separation device 60 and its peripheral mechanisms can be accessed outside the air flow path in the dust removal device 100, when the accumulated amount of the treated oil and the removed solid particles in the separation device 60 increases, or when the oil supplied to the liquid tank 3 decreases, while continuing the operation of the dust removal device 100, access to each device outside can be made to perform operations such as removing the treated oil and solid particles and replenishing clean oil.

[0076] An experimental verification will be described for the promotion of sedimentation of solid particles by the liquid surface heater 62a in the separation device 60 described above.

[0077] Fig. 8 is a graph showing the results of an experiment for verifying the heating of the oil near the surface by the near-infrared type liquid surface heater 62a. As the liquid surface heater 62a, a halogen heater of 200V and 1400W was used, and heating light was irradiated in a state where it was separated from the liquid surface by 30 mm, and the rise in the oil temperature at each depth near the liquid surface was measured.

[0078] In Fig. 8, (A), (B), and (C) show the changes in the oil temperature measured at depths of 0 mm, 5 mm, and 20 mm from the liquid surface, respectively. The actual measurement of the temperature was performed on oil at room temperature of about 25°C. The temperature rise occurred more rapidly closer to the surface. At the liquid surface (Fig. 8(A)), it reached 100°C from room temperature in about 130 seconds, but at a depth of 5 mm from the liquid surface (Fig. 8(B)), it only rose to about 50°C in the same time, and at a depth of 20 mm (Fig. 8(C)), it only rose to just over 30°C.

[0079] The hatching indicated by the dashed lines in each of the diagrams (A), (B), and (C) of Fig. 8 shows the predicted changes in the oil temperature at each depth when heating is performed in the same manner on oil at 0°C based on the above results. According to this, for example, when heating the oil temperature at a depth of 20 mm from 0°C to 20°C, it takes about 300 seconds (see Fig. 8(C)). When the oil is heated for this time, the temperature at the surface rises to nearly 110°C (see Fig. 8(A)). At a depth of 5 mm, it reaches about 80°C (see Fig. 8(B)).

[0080] That is, according to the results of the above experiment, when the oil temperature is 0°C, it is fully possible to raise the oil temperature from the liquid surface to a depth of 20 mm to 20°C by heating for about 5 minutes. At that time, the temperature rise at the liquid surface where the temperature rises most only reaches about 110°C. This is a value sufficiently lower than the flash point and ignition point of general oils used industrially. When considering heating at least the oil up to a depth of 20 mm to about 20°C, it has been demonstrated that it is possible to heat the region near the oil surface quickly and safely.

[0081] Figure 9 shows the results of an experiment in which, for oil mixed with solid particles, after heating for 5 minutes using the same liquid surface heater 62a, the oil near the liquid surface (at a depth of about 20 mm from the liquid surface) was recovered using a float nozzle, and the removal rate of the solid particles contained in the oil was measured. The experiment was conducted in the following procedure. First, oil mixed with solid particles such as volcanic ash was prepared as the treatment target, and the amount per unit volume of the solid particles contained therein was measured by particle size. Next, this oil was stored in an experimental tank, and sedimentation treatment was performed for 5 minutes starting from the state where the oil was at 0°C. The oil near the liquid surface was recovered using a float nozzle, and the amount per unit volume of the solid particles was measured by particle size. The experiment was conducted in two cases: with the irradiation of the heating light by the liquid surface heater 62a turned on and turned off.

[0082] The results with the heating turned on and off are shown by a solid line and a dashed line, respectively, in Figure 9. The solid particles in the oil were compared by particle size for the amount before and after the treatment, and the relative amount after the treatment with respect to the amount before the treatment was shown as the removal rate. Overall, it can be seen that the removal rate is significantly higher when the heating light is irradiated than when it is not irradiated, and the efficiency of the sedimentation treatment is remarkably increased by heating. In particular, there is a large gap between the two for the removal rate of solid particles with a particle size of about 50 μm to 60 μm. Thus, it has been demonstrated that by heating the liquid surface, the necessary sedimentation treatment in the region near the liquid surface can be carried out quickly and efficiently.

[0083] According to the heating method using heating light as described above, the temperature becomes higher and the density becomes smaller closer to the surface, so it is possible to suppress the thermal convection that hinders the sedimentation of solid particles, which is convenient when intending sedimentation treatment. Furthermore, since the intensity of the heating light becomes smaller in deeper regions, it is possible to efficiently and quickly warm only the surface without heating the whole. When considering recovering the oil near the surface as in this embodiment, since it is not necessary to consume the thermal energy for heating other regions and only heat the oil that is the object of recovery, the target oil can be quickly separated with less energy, which is convenient in terms of both the time efficiency and energy efficiency in sedimentation treatment.

[0084] Incidentally, here, as an example of the solid-liquid separation device, the case of applying it to the regeneration of the collected liquid in the dust removal device has been described, but the separation device of the present invention is not limited to this, and can be applied to various cases where it is necessary to separate solid particles from a liquid mixed with solid particles.

[0085] As described above, in the solid-liquid separation method of this embodiment, the sedimentation of solid particles near the liquid surface is promoted by heating the liquid surface of the liquid stored in the sedimentation tank 61 storing the liquid mixed with solid particles.

[0086] Moreover, the solid-liquid separation device 60 of this embodiment includes a sedimentation tank 61 that stores a liquid mixed with solid particles, and a liquid surface heater 62a that heats the liquid surface of the liquid stored in the sedimentation tank 61.

[0087] In this way, when performing the sedimentation treatment of the liquid mixed with solid particles, by heating the liquid from the liquid surface, it is possible to promote the sedimentation of solid particles near the liquid surface while suppressing thermal convection, and perform the sedimentation treatment efficiently.

[0088] In the solid-liquid separation method of this embodiment, among the liquid stored in the sedimentation tank 61, the heated liquid near the liquid surface is recovered as the liquid from which solid particles have been removed.

[0089] In addition, the solid-in-liquid separation device 60 of this embodiment includes a liquid recovery unit 63 that recovers the heated liquid near the liquid surface from the liquid stored in the sedimentation tank 61.

[0090] In this way, sedimentation of solid particles is promoted by heating, and the liquid from which the solid particles have been removed can be efficiently recovered.

[0091] In addition, in the solid-in-liquid separation method of this embodiment, as the liquid surface heater 62a that heats the liquid surface of the liquid stored in the sedimentation tank 61, an optical heater that irradiates heating light is used, and the output of the liquid surface heater 62a is adjusted according to the distance between the liquid surface heater 62a and the liquid surface. In this way, the temperature of the liquid by the liquid surface heater 62a can be appropriately adjusted.

[0092] In addition, in the solid-in-liquid separation device 60 of this embodiment, the liquid surface heater 62a is an optical heater that irradiates heating light. In this way, the liquid surface can be suitably heated.

[0093] In addition, the solid-in-liquid separation device 60 of this embodiment includes a level sensor 62b that measures the liquid level of the liquid stored in the sedimentation tank 61, and is configured to adjust the output of the liquid surface heater 62a according to the measured value of the level sensor 62b. In this way, the temperature of the liquid by the liquid surface heater 62a can be appropriately adjusted.

[0094] Therefore, according to the above-described embodiment, when separating the liquid and solid particles by the sedimentation process, the sedimentation process can be performed simply and suitably.

[0095] Note that the solid-in-liquid separation method and device of the present invention are not limited only to the above-described embodiment, and it goes without saying that various changes can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0096] 60 Separation device 61 Sedimentation tank 62a Liquid surface heater 62b level sensor 63 liquid recovery section

Claims

1. A method for separating solid matter in a liquid, characterized in that, for a sedimentation tank storing a liquid mixed with solid particles, sedimentation of the solid particles near the liquid surface is promoted by heating the liquid surface of the stored liquid.

2. Recovering, as the liquid from which solid particles have been removed, the heated liquid near the liquid surface among the liquid stored in the sedimentation tank The method for separating solid matter in a liquid according to Claim 1, characterized by the above.

3. Using an optical heater that irradiates heating light as a liquid surface heater for heating the liquid surface of the liquid stored in the sedimentation tank, and adjusting the output of the liquid surface heater according to the distance between the liquid surface heater and the liquid surface The method for separating solid matter in a liquid according to Claim 1, characterized by the above.

4. A sedimentation tank for storing a liquid mixed with solid particles, and A liquid surface heater for heating the liquid surface of the liquid stored in the sedimentation tank A device for separating solid matter in a liquid, characterized by comprising the above.

5. The liquid surface heater is an optical heater that irradiates heating light The device for separating solid matter in a liquid according to Claim 4, characterized by the above.

6. Equipped with a level sensor for measuring the liquid level of the liquid stored in the sedimentation tank, The output of the liquid surface heater is adjusted according to the measured value of the level sensor The device for separating solid matter in a liquid according to Claim 5, characterized by the above.

7. Comprising a liquid recovery section for recovering the heated liquid near the liquid surface among the liquid stored in the sedimentation tank The device for separating solid matter in a liquid according to Claim 4, characterized by the above.

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