JP2006248741A - Moisture control device and method for coal ash - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moisture control device for coal ash and its method capable of preventing secondary environmental pollution caused by scattering of the coal ash in a coal ash delivery facility, and of reducing labor of an operator. <P>SOLUTION: This moisture control device 1 for coal ash 2 is adapted to control moisture in the coal ash 2 by a humidifier 100 for humidifying the inputted coal ash 2 by water spray and is characterized by comprising: a moisture sensor 112 for measuring a moisture amount of the coal ash 2 after humidification discharged from the humidifier 100; and a water feed amount control means for controling the amount of the sprayed water based on an output signal from the moisture sensor 112. The moisture in the coal ash 2 is so controled as to set the moisture amount in the coal ash 2 after humidification discharged from the humidifier 100 in the range of 21±3%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for humidifying coal ash, in particular for adjusting and controlling the amount of water, for the purpose of preventing dust scatter during transport of fly ash.

  In coal-fired boiler facilities at coal-fired power plants, about 10% of the amount of coal used for combustion is discharged as coal ash. In recent years, the use of this coal ash has been actively promoted by electric power companies and cement companies, and coal ash is usually carried out to external customers such as the above-mentioned cement companies, particularly in coal-fired power plants. Therefore, there are many places where facilities for temporarily storing coal ash and loading them to trucks and transport ships are set up on the site.

  The coal ash storage and unloading facility is composed of an equipment flow as shown in FIG. 3, for example. Combustion exhaust gas from the boiler 11 passes through each facility of the economizer 12, the denitration device 13, the air preheater 14, the primary electrostatic precipitator 15, and the secondary electrostatic precipitator 16, and coal ash is collected by each of the facilities. The Rotary valves 121, 131, 141, 151, 152, 161, 162 are respectively provided at the lower part of each facility, and the coal ash that has passed through each rotary valve is placed on the coal ash storage silo 30 by the air transport pipe 17. To the cyclone 18 After a part of the coal ash is collected by the cyclone 18, the remaining coal ash in the air is collected by the bag filter 20 through the air pipe 19. Coal ash collected by the cyclone 18 and the bag filter 20 is temporarily stored in the coal ash storage silo 30. When the coal ash is loaded or when the storage silo 30 is full, the forced blower 33 is operated, and the coal ash discharged from the discharge hoppers 31 and 32 under the storage silo is supplied to the coal ash storage silo 40. Transported. The coal ash storage silo 40 communicates with an adjacent coal ash storage silo 42 through a communication pipe 41 so that the coal ash can also be stored in the storage silo 42.

  The coal ash storage silo 40 can be loaded onto the dump truck 49 by operating a predetermined rotary valve below the discharge hopper 43. Further, the coal ash storage silo 42 can be loaded onto the granular material transport vehicle 48 by operating a predetermined rotary valve below the discharge hopper 46.

  When coal ash is sent to a shipping facility on a transport ship, coal ash is supplied to the conveyor 50 by operating predetermined rotary valves and conveyors 45 below the discharge hoppers 44 and 46 of the coal ash storage silos 40 and 42. Thereafter, the coal ash is sent to the coal ash storage yard 54 via the bucket elevator 51 and the conveyors 52 and 53. The coal ash discharged from the lower part of the coal ash storage yard 54 is loaded onto the transport ship 58 by the boom conveyor 57 via the conveyors 55 and 56. Further, by reversing the conveyor 52, it is possible to ship directly without temporarily storing it in the coal ash storage yard 54. In addition, each conveyance conveyor in the conveyance path | route of this plant | facility can consider the flow volume of coal ash etc., and can select the kind and transport capability suitably.

  Regarding the quantitative withdrawal from the coal ash storage silo as described above, for example, Patent Document 1 proposes an ash flow control device.

Japanese Patent Laid-Open No. 2005-22840

  However, in the facility where the coal ash storage silo is loaded onto a dump truck or loaded onto a transport ship, the coal ash is scattered as dust, causing secondary pollution. In the case where coal ash is scattered, in conventional shipping facilities, operators have to carry long hoses to the coal ash storage yard and transport boats, where water must be sprinkled, which requires a lot of labor and time. It was.

  Therefore, the present invention provides a coal ash moisture adjusting device capable of preventing secondary pollution caused by the scattering of coal ash in such coal ash loading facilities and reducing the labor of an operator, and It aims to provide a method.

  According to an aspect of the present invention, the above object is an apparatus for adjusting the moisture of coal ash by a humidifier that humidifies the input coal ash by watering, and the coal ash after humidification discharged from the humidifier This is achieved by a water ash adjustment device for coal ash, characterized by comprising a moisture sensor for measuring the amount of moisture in the water and a water supply amount adjusting means for adjusting the amount of water spray based on an output signal from the moisture sensor.

  In addition, according to another aspect of the present invention, the above object is a coal ash transport including a humidifier that humidifies the input coal ash, and a conveyor that transports the humidified coal ash discharged from the humidifier. This is achieved by a method for adjusting the moisture content of coal ash, characterized in that water is poured into the coal ash in the humidifier so that the moisture content of the coal ash passing through the conveyor falls within a predetermined range.

  The present invention installs a humidifier and waters the coal ash that is put into the humidifier, measures the moisture content of the coal ash after the humidification, and feeds back the measurement result to the amount of water sprayed in the humidifier. By doing so, the moisture content of the coal ash is adjusted to a predetermined range, so that the problem of coal ash scattering does not occur, and the labor required for the operator to spray water can be reduced.

  Hereinafter, the apparatus and method for adjusting the moisture content of coal ash of the present invention will be described in more detail with reference to the drawings. FIG. 1: has shown the schematic flowchart which shows the moisture adjustment apparatus of the coal ash of this invention. In this figure, the moisture ash adjustment device 1 of the present invention includes a humidifier 100 that humidifies the input coal ash by watering, and the moisture content of the coal ash after humidification discharged from the outlet of the humidifier 100. Is constituted by a water supply amount adjusting means constituted by a water supply amount controller 11 and a water supply amount adjustment valve 110.

  A humidifier 100 shown in FIG. 1 includes a cylindrical rotating body having a coal ash charging port 104 at one end and a discharging port 105 at the other end, and the rotating body from the charging port 104 toward the discharging port 105. A downward gradient of 5 to 10 ° is provided in the direction of the axial ship. In addition, a sprinkler tube 101 is provided in the axial direction from the end surface on the discharge port side toward the inlet at a substantially center in the rotating body, and a plurality of sprinkling nozzles 102 are provided in the sprinkler tube 101 at predetermined intervals. , 102, 102,... Are arranged. As the rotating body rotates at a low speed, the coal ash 2 introduced from the introduction port 104 moves while being mixed with water sprinkled toward the discharge port 105. The amount of water sprayed from the plurality of water spray nozzles 102, 102,... Can be appropriately determined in consideration of the flow rate of coal ash, the target value of the moisture amount of coal ash described later, and the like. In addition, as a humidifier used by this invention, it is not limited to the above forms, It cannot be overemphasized that it is mixing mixers, such as a paddle mixer, Comprising: What has a watering apparatus inside can be used. Absent.

  Thereafter, the coal ash 2 discharged from the humidifier 100 is transported to a loading facility on a transport path after the transport conveyor. The conveyor conveyer connected to the outlet of the humidifier 100 is disclosed as a belt conveyor in FIG. 1, but is not particularly limited thereto, and a chain truck conveyor, a belt conveyor, etc. depending on the arrangement of various devices in the coal ash loading path Can be selected as appropriate.

  The moisture amount of the coal ash 2 discharged from the humidifier 100 is measured by the moisture sensor 112. The moisture sensor 112 may be a contact type or a non-contact type. However, in the case of the contact type, the coal ash 2 adheres to a contact portion with the coal ash 2, so a non-contact type sensor is used. preferable. In particular, those capable of continuous measurement can be suitably used. The moisture sensor 112 is not particularly limited as long as it is a non-contact type, and any of an infrared absorption method, a dielectric method, a radiation method, and the like can be used, and can be appropriately selected from these methods. Further, the moisture sensor 112 may be installed above the coal ash passing on the belt conveyor as shown in FIG. 1, but it is installed on the discharge chute 106 of the humidifier 100 and falls in the discharge chute 106. It is also possible to measure the water content of coal ash.

  As shown in FIG. 1, when measuring the moisture content of the coal ash 2 passing on the belt conveyor, from the viewpoint of the measurement accuracy of the moisture sensor 112, an opening provided vertically to the discharge gate 107 of the discharge chute 106. Is preferably formed in a substantially rectangular shape in the width direction of the conveyor belt so that the layer of coal ash 2 is leveled on the belt. Thereby, the distance between the moisture sensor 112 and the layer surface of the coal ash 2 can be made substantially constant, and as a result, improvement in measurement accuracy of the moisture sensor 112 can be expected.

  The moisture sensor 112 outputs the measurement result as an electrical signal to the water supply amount controller via the signal line 113. This electrical signal may be a digital signal or an analog signal. In the latter case, it may be a voltage signal or a current signal. These can be appropriately selected in consideration of the distance between the moisture sensor 112 and the water supply amount controller 111, the specifications of the moisture sensor 112, and the like.

  In the water supply amount controller 111, when the electric signal is input, it is compared with a target value of the water amount, a deviation is obtained, and a control output corresponding to the deviation is output to a water supply amount adjustment valve 110 described later. The In the case of coal ash, the target value of water content is preferably about 21% of the humidified coal ash. In controlling the amount of moisture, various set values such as PID can be set as appropriate. In this case, the control output signal may be an analog signal or a digital signal, like the input signal. Further, when the controller 111 has a communication function, it is possible to transmit the above signals to a central control room (not shown) and to perform remote control from the central control room.

  One end of the water supply amount adjusting valve 110 is provided as a sprinkling pipe 101 in the humidifier 100 and the other end is provided in the middle of the water supply pipe leading to the water source. Based on the control output signal input via the signal line 114. Open and close the valve opening. As a result, the amount of water supply corresponding to the deviation in the controller 111 is increased or decreased, and the water amount is adjusted.

  FIG. 2 shows an equipment flow diagram when the coal ash moisture adjusting device 1 of the present invention shown in FIG. 1 is introduced into the conventional coal ash temporary storage and unloading facility shown in FIG. In addition, in this figure, about the equipment which is common in FIG. 1 and FIG. 2 or is similar, the same code | symbol is used and the overlapping description is abbreviate | omitted.

  The coal ash moisture adjusting device 1 of the present invention is disposed downstream of the coal ash storage silos 40 and 42. In FIG. 2, the moisture sensor is not shown, but it is installed on the conveyor 50 in the same manner as in FIG. The humidifier 100 is supplied with an amount of water necessary for watering from the reservoir 121 by the pump 120.

  In starting the coal ash shipping in the facility shown in FIG. 2, when the coal ash is sent to the coal ash storage yard 54, the humidifier 100 is operated in advance together with the conveyors 45 and 50 to 53. By operating predetermined rotary valves below the discharge hoppers 44 and 45 below the coal storage silos 40 and 42, the coal ash in the coal ash storage silos 40 and 42 is supplied to the humidifier 100. As a method of adjusting the amount of water spray in the humidifier 100 at the time of starting, for example, by opening a water supply amount adjustment valve (see reference numeral 110 in FIG. 2) at a predetermined set opening degree, a predetermined amount of water is supplied to the humidifier 100. Done. Thereafter, when the humidified coal ash reaches the conveyor 50 and can be measured by the moisture sensor, the method is switched to the method for adjusting the moisture content of the coal ash of the present invention, and the moisture signal from the moisture sensor is converted into an electrical signal. Based on the feed water feedback control. Moreover, the coal ash is loaded onto the transport ship 58 by operating the conveyors 55 to 57 from the coal ash storage yard 54.

  By continuously performing the above operation, the moisture content of the coal ash after humidification in each subsequent conveyor, coal ash storage yard 54, and further the transport ship 58 is 21 ± in the coal ash after humidification. It will be adjusted stably to 3%. As a result, the problem of dust scattering in the coal storage 54 and coal dust ash loading into the dump truck 49 or the transport ship 58 is solved.

  As described above, the apparatus and method for adjusting the moisture content of coal ash according to the present invention is a source of coal ash that has been actively used in recent years, particularly coal ash from coal-fired power plants. It is useful for solving the problem of dust scattering at the shipping facility.

It is a schematic flowchart which shows the moisture adjustment apparatus of the coal ash of this invention. FIG. 4 is an equipment flow diagram when the coal ash moisture adjusting device 1 of the present invention shown in FIG. 1 is introduced into the conventional coal ash temporary storage and unloading facility shown in FIG. 3. It is an equipment flow figure of temporary storage and unloading facilities of coal ash.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Moisture adjustment apparatus 100 Humidifier 101 Sprinkling pipe 102 Sprinkling nozzle 110 Water supply amount adjustment valve 111 Water supply amount controller 112 Moisture sensors 113 and 114 Signal line

Claims (5)

  A device for adjusting the moisture of coal ash by a humidifier that humidifies the input coal ash by watering, a moisture sensor for measuring the moisture content of the coal ash after humidification discharged from the humidifier, and the moisture sensor And a water supply amount adjusting means for adjusting the watering amount based on an output signal from the coal ash.   The said moisture sensor is a moisture adjustment apparatus of the coal ash of Claim 1 provided so that the moisture content of the coal ash after the humidification conveyed by the conveyor succeeding to the said humidifier discharge | emission side can be measured.   The discharge chute provided with the discharge gate is provided between the humidifier discharge port and the conveyor, and the opening of the discharge gate is formed in a substantially rectangular shape in the width direction of the conveyor belt. Coal ash moisture adjustment device.   In a coal ash transport path including a humidifier that humidifies the input coal ash and a conveyor that follows the humidifier, the moisture content of the coal ash after being discharged from the humidifier and passing through the conveyor is predetermined. The coal ash moisture adjustment method is characterized in that water is poured into the coal ash in the humidifier so as to be in the range. The moisture adjustment method for coal ash according to claim 4, wherein the moisture content of the coal ash after humidification is adjusted to a range of 21 ± 3% in the humidified coal ash.

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