JP2021084055A - Gas filtration system - Google Patents

Abstract

To provide a gas filtration system capable of more accurately controlling a filling height of a filtration medium.SOLUTION: A gas filtration system includes: a gasification furnace; a filtration device filled with a filtration medium; a gas introduction passage for guiding a combustible gas discharged from the gasification furnace to the filtration device; and a filtration medium supply section supplying the filtration medium to the filtration device. The filtration device includes: a first hollow member in which a filtration space filled with the filtration medium is formed; a second hollow member being inserted into the first hollow member and causing the filtration medium supplied from the filtration medium supply section to drop down to the filtration space; a third hollow member guiding the combustible gas introduced from the gas introduction passage to the filtration space; a filling height detection section detecting a filling height of the filtration medium in the filtration device; and a control section controlling the filtration medium supply section on the basis of a detection result obtained by the filling height detection section so that the filling height of the filtration medium is maintained in the second hollow member.SELECTED DRAWING: Figure 2

Description

The present invention relates to a gas filtration system.

Conventionally, research on a gasifier that thermally decomposes solid waste, biomass, etc. into useful gas components has been widely conducted from the viewpoint of effective use of waste. According to the gasification furnace, the flammable gas (pyrolysis gas) generated in the furnace can be used for various purposes such as power generation, while char (unburned content) in addition to the flammable gas. ), Dust and tar and other by-products are also generated. Therefore, when using flammable gas, it is necessary to remove these by-products from the flammable gas.

This type of technique is described, for example, in Patent Document 1. Patent Document 1 describes a fluidized bed type gasifier that thermally decomposes waste into flammable gas, a filtration tower filled with a filtration medium for adhering by-products contained in the flammable gas, and a sub. The first transport path for sending the filtration medium to which the product is attached from the filtration tower to the gasification furnace as a flow medium, and the flow medium from which the by-products have been removed in the gasification furnace are transferred from the gasification furnace to the filtration tower. The difference between the front and back of the second transport path for sending as a filter medium, the circulation mechanism for circulating the filter medium and the flow medium between the gasifier and the filter tower through the first transport path and the second transport path, and the filtration tower. A waste treatment facility equipped with a differential pressure detection unit for detecting pressure is described. This waste treatment facility fluctuates the circulation amount of the filtration medium and the flow medium so that the differential pressure before and after the filtration tower is within a predetermined range.

Japanese Patent No. 6500157

As described above, the waste treatment facility described in Patent Document 1 controls the differential pressure before and after the filtration tower within a predetermined range, but determines the actual filling height of the filtration medium in the filtration tower. It is difficult to grasp accurately. Therefore, conventionally, there has been a problem that it is difficult to accurately control the filling height of the filtration medium in order to reliably secure the gas filtration function.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas filtration system capable of more accurately controlling the filling height of a filtration medium.

The gas filtration system according to one aspect of the present invention includes a gasifier that thermally decomposes waste into flammable gas, a filtration device filled with a filtration medium for removing by-products from the flammable gas, and the like. It includes a gas introduction path for guiding the flammable gas discharged from the gasifier to the filtration device, and a filtration medium supply unit for supplying the filtration medium to the filtration device. The filtration device includes a first hollow member in which a filtration space filled with the filtration medium is formed, and a second hollow member inserted into the first hollow member, from the filtration medium supply unit. The second hollow member for dropping the supplied filtration medium into the filtration space, the third hollow member for guiding the flammable gas introduced from the gas introduction path to the filtration space, and the inside of the filtration device. The filling height of the filtration medium is maintained within the height range of the second hollow member based on the detection result of the filling height detecting unit that detects the filling height of the filtration medium and the filling height detecting unit. A control unit that controls the filtration medium supply unit is included.

According to this gas filtration system, the filling height detection unit can accurately grasp the filling height of the filtration medium in the filtration device. Then, by controlling the supply of the filtration medium to the filtration device based on the detection result by the filling height detection unit, the supply control of the filtration medium is performed based on the differential pressure before and after the filtration device as in the conventional case. It becomes possible to control the filling height of the filtration medium more accurately.

Moreover, in this gas filtration system, the supply of the filtration medium to the filtration device is controlled so that the filling height of the filtration medium is maintained within the height range of the second hollow member. As a result, the pressure loss in the second hollow member increases due to the presence of the filtration medium, so that the outside air does not flow into the filtration space through the second hollow member even when the inside of the filtration device is maintained at a negative pressure. It can be suppressed.

In the gas filtration system, the control unit brings the filtration medium supply unit into the second hollow member so that the filling height is maintained within the height range of the second hollow member. May be switched between a supply state in which the filtration medium is supplied and a stop state in which the supply of the filtration medium into the second hollow member is stopped.

According to this configuration, unlike the case where the filtration medium is constantly supplied into the second hollow member, it is possible to suppress wear of the piping in the supply path of the filtration medium.

In the gas filtration system, the filling height detection unit includes a projection unit that projects light onto the filtration medium, a light receiving unit that receives the light reflected by the filtration medium, and a light receiving position of the light in the light receiving unit. A data conversion unit that converts the data of the above into data of the filling height of the filtration medium may be included.

According to this configuration, the filling height of the filtration medium can be detected by the non-contact method. Therefore, unlike the case of using the contact type detection unit, it is not necessary to form a mounting hole or the like for mounting the detection unit in the second hollow member, so that the inflow of outside air can be suppressed more reliably.

In the gas filtration system, the control unit may include a storage unit that stores a lower limit value of the filling height and an upper limit value of the filling height. The control unit maintains the filtration medium supply unit in the stopped state while the filling height reaches the upper limit value and then drops to the lower limit value, and when the filling height reaches the lower limit value. The filtration medium supply unit is switched from the stopped state to the supply state, and the filtration medium supply unit is maintained in the supply state while the filling height reaches the lower limit value and then rises to the upper limit value, and the filtration medium supply unit is maintained in the supply state. When the filling height reaches the upper limit value, the filtration medium supply unit may be switched from the supply state to the stop state.

According to this configuration, when controlling the filling height of the filtration medium, the frequency of switching between the supply and the stop of the filtration medium can be reduced, so that the burden on the equipment can be reduced.

In the gas filtration system, the filling height detection unit is attached to the second hollow member, and whether or not the filtration medium is filled in the second hollow member up to the height of the mounting position is determined by the filtration medium. The lower level sensor that detects the presence or absence of contact and the second hollow member are mounted above the lower level sensor, and the second hollow member is filled with the filtration medium up to the height of the mounting position. It may include an upper level sensor that detects whether or not the gas is in contact with the filtration medium. The control unit maintains the filtration medium supply unit in the stopped state after the detection by the upper level sensor until the detection by the lower level sensor is released, and at the time of the detection release by the lower level sensor. The filtration medium supply unit is switched from the stopped state to the supply state, and the filtration medium supply unit is maintained in the supply state until the detection by the upper level sensor is released after the detection is released by the lower level sensor, and the filtration medium supply unit is maintained in the supply state. The filtration medium supply unit may be switched from the supply state to the stopped state at the time of detection by the upper level sensor.

According to this configuration, by using the contact type detection unit, it is possible to easily and surely detect the filling height of the filtration medium.

As is clear from the above description, according to the present invention, it is possible to provide a gas filtration system capable of more accurately controlling the filling height of the filtration medium.

It is a figure which shows typically the structure of the gas filtration system which concerns on Embodiment 1 of this invention. It is a figure which shows typically the structure of the filtration apparatus in Embodiment 1 of this invention. It is a flowchart for demonstrating the control of the filling height of the filtration medium in the said gas filtration system. It is a timing chart for demonstrating the control of the filling height of the filtration medium in the said gas filtration system. It is a schematic diagram for demonstrating the structure of the gas filtration system which concerns on Embodiment 2 of this invention. It is a schematic diagram for demonstrating the modification of this invention. It is a schematic diagram for demonstrating the modification of this invention. It is a schematic diagram for demonstrating the modification of this invention. It is a schematic diagram for demonstrating the modification of this invention. It is a schematic diagram for demonstrating the modification of this invention.

Hereinafter, the gas filtration system according to the embodiment of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
<Gas filtration system>
First, the overall configuration of the gas filtration system 1 according to the first embodiment of the present invention will be described with reference to FIG. In the gas filtration system 1 according to the present embodiment, for example, various wastes such as municipal waste, sewage sludge, woody biomass or waste plastic are gasified in a gasifier 10 to produce flammable gas G1 (synthetic gas, mainly carbon monoxide and hydrogen). This is a system in which the flammable gas G1 is thermally decomposed into (including), filtered by the filtration device 30, and then supplied to various gas utilization destinations. Examples of gas usage destinations include, but are not limited to, gas engines of power generation units. As shown in FIG. 1, the gas filtration system 1 includes a gasifier 10, a filtration device 30, a gas introduction path 20, a gas lead-out path 40, a filtration medium supply section 50, and a filtration medium extraction section 60. , Is mainly provided.

The gasification furnace 10 is a fluidized bed gasification furnace that thermally decomposes the waste into a flammable gas G1. Specifically, the flow medium S1 is flowed by the air sent from the hearth, and the waste thrown into the furnace is dispersed by the flow medium S1. Then, the combustible material is thermally decomposed into the combustible gas G1 by the heat generated when the waste is partially combusted. At this time, in addition to the flammable gas G1, by-products such as unburned components, dust and tar are also generated, and the combustible gas G1 is discharged to the outside of the furnace together with these by-products.

The filtration device 30 is filled with a filtration medium S2 for removing the by-products from the flammable gas G1. As shown in FIG. 1, the filtration device 30 is provided with an inflow port 31 of the flammable gas G1 at the upper portion and an outlet 34 of the combustible gas G1 after filtration is provided at the side portion. Further, the filtration device 30 is provided with a supply port 32 of the filtration medium S2 at the upper part and an extraction portion (extraction pipe) 33 of the filtration medium S2 at the lower part.

The space inside the filtration device 30 is maintained at a negative pressure with respect to the space outside the filtration device 30. As the filtration medium S2, for example, at least one selected from the group consisting of silica sand, olivine sand, calcium oxide, dolomite and slag can be used, but the filtration medium S2 is not limited thereto. The configuration of the filtration device 30 will be described in detail later.

The gas introduction path 20 is a path that guides the flammable gas G1 discharged from the gasifier 10 to the filtration device 30. The upstream end of the gas introduction path 20 is connected to the gas discharge port 11 provided in the upper part of the gasifier 10, and the downstream end is connected to the inflow port 31 of the filtration device 30.

The gas lead-out path 40 is a path through which the filtered flammable gas G1 led out from the filtration device 30 flows. The upstream end of the gas outlet path 40 is connected to the outlet 34 of the filtration device 30, and the filtered flammable gas G1 is supplied to a predetermined gas utilization destination through the gas outlet path 40.

Although not shown, a gas cleaning device such as a scrubber is arranged in the gas lead-out path 40. That is, the filtration device 30 pre-cleans the flammable gas G1 on the upstream side so that the scrubber can clean the flammable gas G1 to the extent that it can be used as fuel.

The filtration medium supply unit 50 supplies the filtration medium S2 to the filtration device 30. As shown in FIG. 1, the filtration medium supply unit 50 in the present embodiment includes a gasifier lower part extraction screw 51, a classification device 52, a medium supply path 53, and a circulation elevator 54.

The lower extraction screw 51 of the gasification furnace is for extracting the flow medium S1 together with the incombustible material from the bottom of the gasification furnace 10 by rotation and sending it to the filtration device 30, and is provided at the lower end of the extraction pipe 14. There is. The classification device 52 is provided at the downstream end of the lower extraction screw 51 of the gasification furnace, and separates the flow medium S1 and the incombustible material by a sieve.

The medium supply path 53 is a path for sending the flow medium S1 separated from the incombustible material by the classification device 52 to the filtration device 30 as the filtration medium S2. As shown in FIG. 1, the upstream end of the medium supply path 53 is connected to the medium outlet 52A (outlet of the flow medium S1) of the classification device 52, and the downstream end is connected to the supply port 32 of the filtration device 30. ing. The circulation elevator 54 conveys the flow medium S1 to a predetermined height that can be supplied to the filtration device 30, and is arranged in the medium supply path 53.

The filtration medium extraction unit 60 has a filtration device lower extraction screw 61 and a medium extraction path 62. The lower extraction screw 61 of the filtration device extracts the filtration medium S2 to the outside of the filtration device 30, and is arranged in the extraction unit 33. In the medium extraction path 62, the upstream end is connected to the downstream end of the lower extraction screw 61 of the filtration device, and the downstream end is connected to the gasifier 10. According to the filtration medium extraction unit 60, the filtration medium S2 extracted to the outside of the filtration device 30 by the rotation of the filtration device lower extraction screw 61 can be sent to the gasification furnace 10 as the flow medium S1.

<Filtration device>
Next, the configuration of the filtration device 30 will be described in detail with reference to FIG. As shown in FIG. 2, the filtration device 30 in the present embodiment has a triple pipe structure, and has a first hollow member 70 (outer pipe) and a second hollow member 80 (middle) inserted in the first hollow member 70. It has a tube) and a third hollow member 90 (inner tube) inserted into the second hollow member 80.

The first hollow member 70 is formed with a filtration space R0 filled with the filtration medium S2. As shown in FIG. 2, the first hollow member 70 is arranged so that the axial direction is along the vertical direction, and the filtration space R0 is formed on the lower side in the first hollow member 70. The first hollow member 70 has a first body portion 71 extending in the pipe axis direction with a substantially constant diameter, and a tapered portion 72 extending downward from the lower end portion of the first body portion 71 while reducing the diameter. doing. An outlet 34 is provided above the filtration space R0 in the first body portion 71, and an extraction portion 33 is provided below the tapered portion 72.

The upper end portion 73 side of the first hollow member 70 is open, and the opening is closed by the flange portion 74. The positions of the outlet 34 and the extraction portion 33 are not limited to the positions shown in FIG. Further, the first hollow member 70 is not limited to the one having the tapered portion 72, and may extend with a substantially constant diameter over the entire axial direction.

The second hollow member 80 is a tube having a diameter smaller than that of the first hollow member 70 and a diameter larger than that of the third hollow member 90, and the filtration medium S2 supplied from the filtration medium supply unit 50 (FIG. 1) is used as a filtration space. Drop it to R0. As shown in FIG. 2, the second hollow member 80 is arranged with a radial gap between the first hollow member 70 (first body portion 71) and the third hollow member 90. Then, the filtration medium S2 supplied from the filtration medium supply unit 50 falls into the filtration space R0 through the annular gap between the second hollow member 80 and the third hollow member 90.

The second hollow member 80 is inserted into the first hollow member 70 so that the axial direction is along the vertical direction and is coaxial with the first hollow member 70 and the third hollow member 90. More specifically, the second hollow member 80 extends in the axial direction with a substantially constant diameter and is connected to the second body portion 81 arranged in the first body portion 71 and the upper end portion of the second body portion 81. It also has an extending portion 82 extending upward from the upper end portion 73 of the first hollow member 70.

As shown in FIG. 2, the lower end 83 of the second hollow member 80 is located above the lower end 91 of the third hollow member 90 and below the outlet 34. Further, the extending portion 82 extends from the upper end portion of the second body portion 81 while increasing its diameter upward. The second body portion 81 is surrounded by the first hollow member 70, while the extension portion 82 is not surrounded by the first hollow member 70 and is in an exposed state.

The third hollow member 90 is a pipe having a diameter smaller than that of the first hollow member 70 and the second hollow member 80, and guides the flammable gas G1 introduced from the gas introduction path 20 (FIG. 1) to the filtration space R0. As shown in FIG. 2, the third hollow member 90 is placed in the second hollow member 80 so that the axial direction is along the vertical direction and is coaxial with the first hollow member 70 and the second hollow member 80. It has been inserted.

The third hollow member 90 has an upper end portion 92 and a lower end portion 91, and extends from the upper end portion 92 to the lower end portion 91 with a substantially constant diameter. Further, in the third hollow member 90, the upper end portion 92 is located above the upper end portion 73 of the first hollow member 70, the lower end portion 91 is below the outflow port 34, and the first body portion 71 and the tapered portion are tapered. It is located above the boundary with 72.

The flow of the flammable gas G1 in the filtration device 30 in the present embodiment is as follows. In FIG. 2, the flow of the flammable gas G1 is indicated by a broken line arrow.

First, the flammable gas G1 in the gas introduction path 20 (FIG. 1) is introduced into the third hollow member 90 through the opening on the upper end portion 92 side. That is, the opening on the upper end 92 side of the third hollow member 90 is the inflow port 31 (FIG. 1) of the flammable gas G1. Then, the flammable gas G1 flows in the third hollow member 90 from the upper end portion 92 toward the lower end portion 91, and flows into the filtration space R0 from the opening on the lower end portion 91 side.

In the process of the flammable gas G1 passing through the filtration space R0, the by-product adheres to the filtration medium S2, and the by-product is removed from the flammable gas G1. Then, the flammable gas G1 flows upward in the packed bed of the filtration medium S2, and is between the first hollow member 70 (first body portion 71) and the second hollow member 80 (second body portion 81). After passing through the annular gap of the above, the gas flows out of the filtration device 30 from the outlet 34.

Next, the supply of the filtration medium S2 to the filtration device 30 and the extraction of the filtration medium S2 from the filtration device 30 will be described.

First, the flow medium S1 sent from the gasification furnace 10 through the medium supply path 53 (FIG. 1) is supplied as the filtration medium S2 into the second hollow member 80 (extended portion 82) from above. The supplied filtration medium S2 falls in the annular space between the second hollow member 80 and the third hollow member 90, and fills the filtration space R0. Then, even after the filtration medium S2 is filled in the filtration space R0, the filtration medium S2 is further supplied, so that the filtration medium S2 is also filled in the second hollow member 80 to a certain height as shown in FIG. Will be done. On the other hand, at the time of extraction, the filtration medium S2 filled in the filtration space R0 falls from the extraction unit 33 to the outside of the filtration device 30 by rotating the extraction screw 61 (FIG. 1) at the bottom of the filtration device.

The filtration device 30 further includes a filling height detecting unit 100 that detects the filling height of the filtration medium S2 in the filtration device 30. The filling height detection unit 100 in this embodiment is composed of a reflection type laser displacement sensor.

Specifically, the filling height detecting unit 100 receives a light receiving unit 101 that projects a laser beam 104 onto the upper surface of the filling layer of the filtration medium S2 and a laser beam 104 (reflected light 105) reflected on the upper surface. It has a part 102 and. When the filling height of the filtration medium S2 changes, the light receiving position of the reflected light 105 in the light receiving unit 102 also changes accordingly. The filling height detection unit 100 has a data conversion unit 103 that converts the data of the light receiving position of the reflected light 105 in the light receiving unit 102 into the data of the filling height of the filtration medium S2, thereby filling the filtration medium S2. The height (height position of the upper surface of the packed bed of the filtration medium S2) can be detected.

The filtration device 30 controls the filtration medium supply unit 50 so that the filling height of the filtration medium S2 is maintained within the height range of the second hollow member 80 based on the detection result by the filling height detecting unit 100. It further has a control unit 110. The control unit 110 supplies the filtration medium S2 into the second hollow member 80 so that the filling height of the filtration medium S2 is maintained within the height range of the second hollow member 80. The state is switched between the supply state and the stop state in which the supply of the filtration medium S2 into the second hollow member 80 is stopped. More specifically, in the control unit 110, the filling height of the filtration medium S2 detected by the filling height detecting unit 100 is within the height range H1 of the pipe extending portion 82 of the second hollow member 80. Controls the filtration medium supply unit 50.

As shown in FIG. 2, the control unit 110 stores a data receiving unit 111 that receives data on the filling height of the filtration medium S2 from the filling height detecting unit 100, and stores the lower limit value L1 and the upper limit value L2 of the filling height. It has a storage unit 112, and a screw control unit 113 for switching the rotation and stop of the lower extraction screw 51 of the gasifier and the lower extraction screw 61 (FIG. 1) of the filtration device. As shown in FIG. 2, both the lower limit value L1 and the upper limit value L2 are located within the height range H1 of the extension portion 82. Hereinafter, control of the filling height of the filtration medium S2 by the control unit 110 will be described with reference to the flowchart of FIG. 3 and the timing chart of FIG.

<Control of filling height of filtration medium>
First, the filtration medium S2 is filled into the filtration device 30 before the steady operation of the gas filtration system 1 is started, that is, before the introduction of the flammable gas G1 from the gasifier 10 into the filtration device 30 is started (). Step S10). Specifically, the control unit 110 rotates the lower extraction screw 51 of the gasification furnace in a state where the filtration medium S2 is not filled in the filtration device 30.

As a result, the filtration medium S2 is supplied into the second hollow member 80 through the opening on the upper end side of the second hollow member 80 through the medium supply path 53 (FIG. 1), and the supplied filtration medium S2 becomes the second hollow member. The filtration medium S2 is filled in the filtration space R0 by falling into the filtration space R0 through the annular gap between the 80 and the third hollow member 90. Then, by continuing to supply the filtration medium S2 even after the filtration space R0 is filled with the filtration medium S2, the filling height of the filtration medium S2 in the second hollow member 80 is increased.

The control unit 110 compares the detection data by the filling height detecting unit 100 with the upper limit value L2, and rotates the gasifier lower part extraction screw 51 until the filling height of the filtration medium S2 reaches the upper limit value L2. Continue (NO in step S20). Then, when the filling height reaches the upper limit value L2 (YES in step S20), the control unit 110 stops the rotation of the gasifier lower part extraction screw 51 and stops the supply of the filtration medium S2 to the filtration device 30. (Step S30). At this time, the control unit 110 turns on the upper limit flag. Hereinafter, control of the filling height of the filtration medium S2 during the steady operation of the gas filtration system 1 will be described.

When the rotation of the lower extraction screw 51 of the gasification furnace is stopped, the rotation of the lower extraction screw 61 of the filtration device is started, and the filtration medium S2 is extracted from the filtration device 30 by the lower extraction screw 61 of the filtration device. The filling height is lowered. After the filling height reaches the upper limit value L2, the control unit 110 keeps the filtration medium supply unit 50 (gasification furnace lower part extraction screw 51) in the stopped state while the filling height falls to the lower limit value L1 (in step S40). NO). Then, when the filling height reaches the lower limit value L1 (YES in step S40), the control unit 110 switches the filtration medium supply unit 50 (gasification furnace lower part extraction screw 51) from the stopped state to the supply state (step). S50). At this time, the control unit 110 turns off the upper limit flag and turns on the lower limit flag. As described above, when the filling height is between the lower limit value L1 and the upper limit value L2 and the upper limit flag is on, the control unit 110 puts the gasifier lower part extraction screw 51 in the stopped state.

As a result, the supply of the filtration medium S2 to the filtration device 30 is restarted, and the filling height of the filtration medium S2 in the second hollow member 80 is increased. The control unit 110 maintains the filtration medium supply unit 50 (gasification furnace lower extraction screw 51) in the supply state while the filling height reaches the lower limit value L1 and then rises to the upper limit value L2 (step S60). NO). Then, when the filling height reaches the upper limit value L2 (YES in step S60), the control unit 110 switches the filtration medium supply unit 50 (gasification furnace lower part extraction screw 51) from the supply state to the stopped state (step). S70). At this time, the control unit 110 turns off the lower limit flag and turns on the upper limit flag. As described above, when the filling height is between the lower limit value L1 and the upper limit value L2 and the lower limit flag is on, the control unit 110 maintains the rotating state of the gasifier lower part extraction screw 51.

Then, when the end condition of the control of the filling height is not satisfied (NO in step S80), for example, when the gas filtration system 1 is in steady operation, the process returns to step S40, and the gasifier lower part extraction screw 51 The rotation and its stop are repeated. On the other hand, when the termination condition is satisfied (YES in step S80), the control of the filling height of the filtration medium S2 is terminated.

As described above, according to the gas filtration system 1 according to the present embodiment, the filling height detecting unit 100 can accurately grasp the filling height of the filtration medium S2 in the filtration device 30. Then, by controlling the supply of the filtration medium S2 to the filtration device 30 based on the detection result by the filling height detection unit 100, the supply control of the filtration medium S2 is performed based on the differential pressure before and after the filtration device 30. It becomes possible to control the filling height of the filtration medium S2 more accurately as compared with the above.

Moreover, the gas filtration system 1 employs a filtration device 30 having a triple-tube structure, and a filtration medium for the filtration device 30 so that the filling height of the filtration medium S2 is maintained in the second hollow member 80. Control the supply of S2. As a result, the pressure loss in the second hollow member 80 is increased by the filtration medium S2, so that outside air flows into the filtration space R0 through the second hollow member 80 even when the inside of the filtration device 30 is maintained at a negative pressure. Can be suppressed.

(Embodiment 2)
Next, the gas filtration system according to the second embodiment of the present invention will be described with reference to FIG. The gas filtration system according to the second embodiment basically has the same configuration as the gas filtration system 1 according to the first embodiment and has the same effect, but a contact type sensor is used as a filling height detection unit. It differs in that it is used. Hereinafter, only the points different from the first embodiment will be described.

The filling height detection unit 100A in the present embodiment is attached to the lower level sensor 101A attached to the extension portion 82 of the second hollow member 80 and above the lower level sensor 101A of the extension portion 82. It also has an upper level sensor 101B. Both the lower level sensor 101A and the upper level sensor 101B detect whether or not the second hollow member 80 is filled with the filtration medium S2 up to the height of the mounting position by the presence or absence of contact with the filtration medium S2. It is a sensor. Specifically, the lower level sensor 101A and the upper level sensor 101B are capacitance sensors that detect static electricity in the filtration medium S2, and penetrate the extending portion 82 in the radial direction so as to be in contact with the filtration medium S2. doing. Further, the lower level sensor 101A is arranged at the height position of the lower limit value L1 described in the first embodiment, and the upper level sensor 101B is arranged at the height position of the upper limit value L2 described in the first embodiment.

According to the filtration device 30A in the present embodiment, the filling height of the filtration medium S2 is set in the second hollow member 80 (the height of the extending portion 82) by the same control as in FIGS. 3 and 4 described in the first embodiment. It can be controlled within the range H1). That is, the control unit 110 maintains the filtration medium supply unit 50 (gasifier lower extraction screw 51) in the stopped state until the detection by the lower level sensor 101A is canceled after the detection by the upper level sensor 101B. At the same time, the filtration medium supply unit 50 (gasification furnace lower extraction screw 51) is switched from the stopped state to the supply state when the detection by the lower level sensor 101A is released. Further, the control unit 110 maintains the filtration medium supply unit 50 (gasifier lower extraction screw 51) in the supply state after the detection is released by the lower level sensor 101A until the detection by the upper level sensor 101B, and the upper level. At the time of detection by the sensor 101B, the filtration medium supply unit 50 (screw 51 extracted from the lower part of the gasifier) is switched from the supply state to the stopped state.

It should be understood that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims. Therefore, the scope of the present invention also includes the following modifications.

In the filtration devices 30 and 30A according to the first and second embodiments, the first body portion 71 has a circular tube shape, the tapered portion 72 has a substantially conical shape, and the extraction portion 33 has a larger than the first body portion 71. It has a small diameter circular tube shape, but is not limited to this. For example, the first body portion may have a quadrangular tube shape, the tapered portion may have a substantially quadrangular pyramid shape, and the extraction portion may have a quadrangular tube shape having a diameter smaller than that of the first body portion. Further, the tapered portion 72 has a substantially conical shape or a substantially quadrangular pyramid shape, because at least a part of the side surface thereof is inclined with respect to the axial direction so as to reduce the diameter downward. It is possible to suppress clogging of the filtration medium S2.

In the first and second embodiments, the case where the third hollow member 90 is inserted into the second hollow member 80 has been described as an example, but the present invention is not limited to this. As shown in FIG. 6, the third hollow member 90 is inserted into the first hollow member 70 so as to extend upward from the bottom side of the first hollow member 70, and the upper end surface 93 thereof is the lower end portion of the second hollow member 80. It may be located below 83. In this case, as shown in FIG. 7, the upper end portion of the third hollow member 90 may be bent at a substantially right angle so that the filtration medium S2 does not enter the third hollow member 90.

Further, as shown in FIG. 8, the third hollow member 90 penetrates the side portion of the first hollow member 70 (first body portion 71) below the lower end portion 83 of the second hollow member 80 and is said to be the first. 1 It may be inserted into the hollow member 70 (the second hollow member 80 and the third hollow member 90 are substantially at right angles). In this case, as shown in FIG. 9, an L-shaped branch portion 94 is provided on the side portion of the third hollow member 90 so that the flammable gas is supplied to the filtration space from the tip surface 94A of the branch portion 94. It may be configured as. Further, as shown in FIG. 10, the third hollow member 90 is inserted into the first hollow member 70 in parallel with the second hollow member 80 without being inserted into the second hollow member 80, and the lower end surface 95 thereof. May be located below the lower end 83 of the second hollow member 80. In each of the modified examples of FIGS. 6 to 10, only one third hollow member 90 may be provided, but the present invention is not limited to this, and a plurality of third hollow members 90 may be provided.

The first to third hollow members 70, 80, 90 may all have a circular tube shape or a square tube shape, but are not limited thereto. That is, the first to third hollow members 70, 80, 90 may have different shapes.

In the first and second embodiments, the case where the second hollow member 80 has the extension portion 82 has been described, but the extension portion 82 may be omitted. Even in this case, by ensuring a sufficient length of the second hollow member 80, it is possible to suppress the inflow of outside air into the filtration space through the second hollow member. In this case, the second hollow member 80 may have a constant diameter as a whole, or has a portion having a constant diameter and a diameter-expanded portion whose diameter increases from the upper end of the portion toward the upper side. The upper end of the enlarged diameter portion may be connected to the lower surface of the flange portion 74.

The filtration devices 30 and 30A according to the first and second embodiments include a clogging detecting means for detecting clogging of the filtration medium S2 in the lower portion of the first hollow member 70 and the extraction portion 33, and a clogging clearing means for clearing the clogging. , May be further provided.

As an example of the clogging detecting means, the filling height of the filtration medium S2 and the pressure loss of the filtration media 30 and 30A occur while the supply of the filtration medium S2 to the filtration devices 30 and 30A is stopped (S30 to S50 in FIG. 3). A determination unit that determines that the filtration medium S2 is clogged based on the fact that it does not decrease (or the rate of decrease is small) may be provided as one function of the control unit 110. When the pressure loss of the filtration devices 30 and 30A is used as an index for clogging detection, pressure gauges are provided before and after the filtration devices 30 and 30A (each of the gas introduction path 20 and the gas lead-out path 40).

As another clogging detecting means, a determination unit that determines that clogging of the filtration medium S2 has occurred is controlled based on the fact that the weight of the filtration devices 30 and 30A does not decrease (or the decrease rate is small) during the supply stop. It may be provided as one function of the unit 110. In this case, a weighing scale (load cell) for measuring the weight of the filtration devices 30 and 30A is provided. As yet another clogging detecting means, the control unit 110 determines that the filtration medium S2 is clogged based on the vibration and sound of the filtration devices 30 and 30A becoming smaller than a certain level during the supply stop. It may be provided as one function. In this case, a sensor for detecting vibration and sound of the filtration devices 30 and 30A is provided. Further, as the clogging clearing means, a knocker (hammering) or a vibrating device can be used.

The filtration devices 30 and 30A in the first and second embodiments may further include a filtration medium storage unit for storing the filtration medium S2 before being supplied to the filtration devices 30 and 30A. This filtration medium storage section is provided as a buffer section of the filtration medium S2 in the medium supply path 53 (FIG. 1). As a result, the filtration medium S2 can be supplied from the filtration medium storage unit to the filtration devices 30 and 30A even when the flow medium S1 is not extracted from the gasification furnace 10.

The filtration devices 30 and 30A according to the first and second embodiments further include a heater (heating unit) wound around the outer periphery of the first body portion 71, the tapered portion 72, the extraction portion 33 and the extension portion 82. May be good. By heating the filtration devices 30 and 30A with this heater, by-products such as tar that are accompanied by the flammable gas G1 and introduced into the filtration devices 30 and 30A are condensed in the filtration devices 30 and 30A. Can be suppressed.

In the first embodiment, the fluidized bed gasification furnace has been described as an example of the gasification furnace, but the present invention is not limited to this, and a fixed bed downdraft gasification furnace, a fixed bed updraft gasification furnace, and the like can also be applied. is there.

In the first embodiment, the case where the flow medium S1 in the gasification furnace 10 is sent to the filtration device 30 as the filtration medium S2 has been described, but the present invention is not limited to this, and even if another supply source of the filtration medium S2 is provided. Good.

In the first embodiment, only the supply control of the filtration medium S2 based on the height of the packed bed has been described, but the supply control of the filtration medium S2 based on the differential pressure before and after the filtration device 30 may be performed at the same time.

10 Gasifier 20 Gas introduction path 30, 30A Filtration device 50 Filtration medium supply part 70 First hollow member 73 Upper end part 80 Second hollow member 82 Extension part 90 Third hollow member 100, 100A Filling height detection part 101 Projection Unit 101A Lower level sensor 101B Upper level sensor 102 Light receiving unit 103 Data conversion unit 110 Control unit 112 Storage unit G1 Combustible gas R0 Filtration space S2 Filtration medium

Claims (5)

A gasifier that thermally decomposes waste into flammable gas,
A filtration device filled with a filtration medium for removing by-products from the flammable gas,
A gas introduction path for guiding the combustible gas discharged from the gasifier to the filtration device, and
The filtration device is provided with a filtration medium supply unit for supplying the filtration medium.
The filtration device
A first hollow member in which a filtration space filled with the filtration medium is formed,
A second hollow member inserted into the first hollow member, the second hollow member for dropping the filtration medium supplied from the filtration medium supply unit into the filtration space.
A third hollow member that guides the flammable gas introduced from the gas introduction path to the filtration space, and
A filling height detection unit that detects the filling height of the filtration medium in the filtration device, and
Based on the detection result by the filling height detecting unit, a control unit that controls the filtration medium supply unit so that the filling height of the filtration medium is maintained within the height range of the second hollow member. Including gas filtration system. The control unit is in a supply state in which the filtration medium supply unit supplies the filtration medium into the second hollow member so that the filling height is maintained within the height range of the second hollow member. The gas filtration system according to claim 1, wherein the gas filtration system is switched between a stopped state in which the supply of the filtration medium into the second hollow member is stopped. The filling height detection unit is
A projection unit that projects light onto the filtration medium,
A light receiving unit that receives the light reflected by the filtration medium and
The gas filtration system according to claim 2, further comprising a data conversion unit that converts data on the light receiving position of the light receiving unit into data on the filling height of the filtration medium. The control unit includes a storage unit that stores a lower limit value of the filling height and an upper limit value of the filling height.
The control unit
While the filling height reaches the upper limit value and then decreases to the lower limit value, the filtration medium supply unit is maintained in the stopped state, and when the filling height reaches the lower limit value, the filtration medium supply unit is maintained. Is switched from the stopped state to the supply state,
While the filling height reaches the lower limit value and then rises to the upper limit value, the filtration medium supply unit is maintained in the supply state, and when the filling height reaches the upper limit value, the filtration medium supply unit is maintained. The gas filtration system according to claim 3, wherein the gas filtration system is switched from the supply state to the stop state. The filling height detection unit is
A lower level sensor that is attached to the second hollow member and detects whether or not the second hollow member is filled with the filtration medium up to the height of the mounting position based on the presence or absence of contact with the filtration medium.
Whether or not the second hollow member is attached to the upper side of the lower level sensor and the second hollow member is filled with the filtration medium up to the height of the attachment position is whether or not there is contact with the filtration medium. Including the upper level sensor, which is detected by
The control unit
After the detection by the upper level sensor, the filtration medium supply unit is maintained in the stopped state until the detection by the lower level sensor is released, and when the detection by the lower level sensor is released, the filtration medium supply unit is released. From the stopped state to the supply state,
The filtration medium supply unit is maintained in the supply state from the release of the detection by the lower level sensor to the detection by the upper level sensor, and the filtration medium supply unit is released from the supply state at the time of detection by the upper level sensor. The gas filtration system according to claim 2, which switches to the stopped state.

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