JP7054477B2 - Raw material storage method - Google Patents

Description

The present invention relates to a raw material pile formed by stacking spontaneously ignitable raw materials used as fuel for a raw material combustion facility, for example, a coal pile formed by stacking coal used as fuel for a boiler of a power plant. Regarding the method of storing raw materials to be stored in the storage area.

Traditionally, coal used as fuel for boilers in power plants has been unloaded from transport vessels into storage areas. In the storage area, coal is stored as a pile of coal formed. As the coal used as fuel for the boiler, for example, bituminous coal and subbituminous coal are mixed at a predetermined ratio, and the subbituminous coal has higher spontaneous combustion property than the bituminous coal and has a long-term ignition property. Since it spontaneously ignites when stored, it is cut from the coal pile at an early stage and transported to the boiler.

When cutting coal from a coal mine, a reaping device is used. To prevent accidental cutting of the ground in the storage area with the reaping device, the minimum of the coal mine as a non-cutting area at the bottom of the coal mine. Thickness dimensions are specified. Therefore, the uncut bottom layer of the coal mine corresponding to the minimum thickness dimension remains in the storage area. If this bottom layer contains highly pyrophoric subbituminous coal, it may ignite from the bottom layer during the storage period.

By the way, Patent Document 1 provides a method for predicting spontaneous combustion of coal having high pyrophoricity. This spontaneous combustion prediction method for coal is a method for predicting the temperature distribution inside the coal mine based on the physical property values of the stored coal.

JP-A-2015-132575

The conventional method for predicting spontaneous combustion of coal merely predicts spontaneous combustion, and cannot suppress spontaneous combustion itself. It should be noted that this is not limited to the case of coal, but is common to all pyrophoric raw materials that are piled up and stored.

Therefore, an object of the present invention is to provide a raw material storage method capable of suppressing spontaneous combustion by a spontaneously ignitable raw material.

In the raw material storage method of the present invention, the spontaneously ignitable raw materials are piled up and stored as a raw material pile, and the raw material is cut from the raw material pile and transported to the raw material combustion facility on the ground of the storage area. A raw material having a lower bottom layer thicker than the minimum thickness dimension of the raw material mountain for defining a bottom layer in which the raw material mountain is not cut is formed, and a raw material having higher pyrophoricity than the raw material of the lowest layer is formed on the bottom layer. It is characterized in that a raw material pile is formed by stacking piles of the above to form a main body layer.

In the raw material storage method having the above configuration, a raw material is formed by stacking raw materials having higher spontaneous combustion than the raw material of the lowest layer on the lowermost layer thicker than the minimum thickness dimension to form a main body layer. Since it forms a mountain, if it is cut to the minimum thickness when cutting, it is suppressed that the bottom layer of the raw material mountain that is not cut contains a highly spontaneously ignitable raw material, and the raw material is highly spontaneously ignited. Spontaneous combustion can be suppressed.

In the present invention, it is also possible to adopt a configuration in which a raw material mountain is formed by cutting the mountaintop portion of the main body layer after forming the main body layer.

In the above configuration, by cutting the mountaintop portion of the main body layer formed by stacking highly spontaneously ignitable raw materials, the air permeability to the inside of the main body layer is improved, the heat dissipation inside the main body layer is improved, and the main body is improved. Spontaneous combustion from the layer can be effectively suppressed.

The raw material storage method according to the present invention can suppress spontaneous combustion due to spontaneous combustion raw materials.

FIG. 1 is a schematic plan view showing the configuration of a storage area used in the raw material storage method according to the embodiment of the present invention. 2A is a front view showing the stacker of FIG. 1, and FIG. 2B is a front view showing the reclaimer of FIG. FIG. 3 is an explanatory diagram of a raw material storage method according to an embodiment of the present invention, and FIG. 3A is a diagram in which the bottom layer of a coal mine thicker than the minimum thickness dimension is formed on the ground of a storage area. 3 (b) is a diagram of a coal mine formed by stacking a main body layer on the bottom layer, and FIG. 3 (c) is a diagram of a coal mine formed by cutting the peak portion of the main body layer. FIG. 4 is an explanatory diagram of the raw material storage method according to the same embodiment, and is an explanatory diagram when coal is cut from the coal mine of FIG. 3 (c).

A raw material storage method according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the raw material combustion facility that burns the spontaneously ignitable raw material is used as a boiler of the power plant, and the raw materials used as the fuel are bituminous coal among coals and more spontaneously ignitable than the bituminous coal. High subbituminous coal.

First, a storage area for storing coal will be described. As shown in FIG. 1, the storage area 1 has a rectangular site in a plan view extending from the transport ship 2 toward the boiler 3 of the power plant.

The storage area 1 includes a carry-in rail 10 arranged along the longitudinal direction on one side of the storage area 1, a carry-out rail 11 arranged along the longitudinal direction on the other side of the storage area 1, and a carry-in rail 10. A plurality of first rails 12 arranged in parallel with the carry-out conveyor 11 at predetermined intervals along the lateral direction of the storage area 1, and the first rail 12 between the first rails 12. A plurality of second rails 13 arranged in the same manner as the rail 12, a first relay conveyor 14 arranged on the first rail 12, and a second relay conveyor arranged on the second rail 13. Between the 15 and the stacker 5 provided so as to be able to run on the first rail 12, the reclaimer 6 provided so as to be able to run on the second rail 13, and between the first rail 12 and the second rail 13. It is provided with a work space 16 provided.

The carry-in conveyor 10 is connected to the first relay conveyor 14 and conveys coal carried in from the transport ship 2 from the carry-in conveyor 10 to the boom conveyor 530 of the stacker 5 via the first relay conveyor 14.

The carry-out conveyor 11 is connected to the second relay conveyor 15, and receives the coal cut by the boom conveyor 630 of the reclaimer 6 from the second relay conveyor 15 and carries it out to the boiler 3.

The work space 16 is a space as a ground forming the coal mine 4, and has a rectangular site in a plan view capable of forming a plurality of coal mine. In the work space 16, the coal is divided and stored as a coal mine 4 according to the type of coal and the place of origin. The stacker 5 and the reclaimer 6 are arranged to face each other on both sides of the work space 16, and the stacker 5 piles up the coal unloaded from the transport ship 2 to a plurality of coal piles 4 (see FIG. 3). Is formed, coal is harvested from the coal mine 4 by the reclaimer 6, and is transported to the boiler 3 of the power plant by the second relay conveyor 15 and the unloading conveyor 11.

The stacker 5 is a traveling loading machine for stacking coal in the work space 16 to form a coal pile 4, and is arranged so as to straddle the first relay conveyor 14 as shown in FIG. 2 (a). A bogie 50 that travels along the first rail 12, a vertical rotation shaft 51 that is rotatably supported on the upper surface of the bogie 50, and a structure that can turn around the rotation shaft 51. Coal 52, an arm 53 rotationally supported by the machine 52 with a base end as a fulcrum, and a vertical rotation of the arm 53 and a turn around the rotation axis 51 of the machine 52. It is provided with a drive operation unit 54.

A boom conveyor 530 arranged along the extending direction of the arm 53 is arranged on the arm 53. The boom conveyor 530 is connected to the first relay conveyor 14. The coal is loaded into the work space 16 via the carry-in conveyor 10 laid on the ground of the storage area 1, the first relay conveyor 14, and the boom conveyor 530.

The reclaimer 6 is a traveling type payout machine for reaping the coal of the coal mine 4, and is arranged so as to straddle the second relay conveyor 15 as shown in FIG. 2 (b), and is arranged on the second rail 13. A dolly 60 traveling along the trolley 60, a vertical rotation shaft 61 rotatably supported on the upper surface of the trolley 60, a machine body 62 configured to be able to turn around the rotation shaft 61, and the machine body. An arm 63 that is rotationally supported in the vertical direction with the base end as a fulcrum, a drive operation unit 64 that rotates the arm 63 in the vertical direction and turns around the rotation shaft 61 of the machine body 62, and an arm 63. A bucket wheel 65 rotatably supported at the tip is provided. A boom conveyor 630 is arranged on the arm 63 along the extending direction of the arm 63, and coal is carried out from the boom conveyor 630 to the boiler 3 via the second relay conveyor 15 and the carry-out conveyor 11.

Next, the raw material storage method will be described. First, as shown in FIG. 3A, the operator moves the bucket wheel 65 of the reclaimer 6 to the coal pile 4 made of bituminous coal formed in the work space 16 and rotates the bucket wheel 65. The main body layer shown by the chain line in FIG. 3A is dispensed so that the thickness H2 of the lowermost layer 41 is, for example, 0.8 m.

The thickness H2 of the bottom layer 41 is defined as the height H2 from the ground of the bottom layer 41, and the area where the coal pile 4 is not cut so as not to cut the ground of the work space 16 (the ground of the storage area 1). The bottom layer 40 is formed to be thicker (for example, 0.8 m) than the minimum thickness dimension (for example, 0.5 m) for defining H1. That is, the lowermost layer 41 is a layer in which bituminous coal is further piled up on the bottom layer 40. The lowermost layer 41 is a layer that becomes the bottom of the coal mine 4, is thicker than the bottom layer 40 that is not cut, and its upper surface is formed substantially flat. By forming the upper surface of the lowermost layer 41 flat in this way, it is possible to suppress the subbituminous coal forming the main body layer 42 from being mixed into the lowermost layer 41. The lowermost layer 41 is formed to be, for example, about 0.2 m to 0.5 m thicker than the thickness H1 of the bottom layer 40.

Next, the worker carries in raw materials such as subbituminous coal from the transport ship 2 via the carry-in conveyor 10, and then feeds the subbituminous coal, which has higher pyrophoricity than bituminous coal, to the boom conveyor 530 of the stacker 5 via the first relay conveyor 14. Carry in. Next, as shown in FIG. 3B, the operator moves the tip of the stacker 5 to a position at a height of about 2 m from the summit of the coal mine 4 to be formed. This height is always controlled by the sensor. Next, the worker rotates the arm 53 around the rotation shaft 51 while driving the boom conveyor 530, and piles the subbituminous coal, which has higher pyrophoricity than the bituminous coal of the lowest layer 41, on the lowermost layer 41. A ridge-shaped main body layer 42 is formed, and a coal ridge 4 having a height H3 (for example, 12 m) above the ground is formed. The main body layer 42 is piled up so that the mountain-shaped inclination is continuous with the side surface inclination of the lowermost layer 41. Further, at this point, the mountaintop of the main body layer 42 has a substantially sharp shape.

Next, as shown in FIG. 3C, the operator moves the bucket wheel 65 of the reclaimer 6 to the peak portion of the coal pile 4, rotates the bucket wheel 65, and cuts the peak portion of the main body layer 42. The main body layer 42 is formed in a substantially trapezoidal shape, and is stored for a predetermined period as a coal pile 4 having a height H4 (for example, 9 m) above the ground. At this point, a flat top surface is formed on the top of the main body layer 42. As a result, the air permeability to the inside of the main body layer 42 is improved, the heat dissipation inside the main body layer 42 is improved, and spontaneous combustion from the main body layer 42 can be suppressed during the storage period. The cutting of the chevron portion of the main body layer 42 is about 1 m to 4 m.

Next, when the coal of the coal mine 4 is used as the fuel of the boiler 3, the worker cuts the coal from the stored coal mine 4 as shown in FIG. Specifically, the operator moves the bucket wheel 65 of the reclaimer 6 to the flat peak portion of the coal mine 4, and while rotating the bucket wheel 65, rotates the arm 63 around the rotation shaft 61. , The coal pile 4 is cut in a stepwise manner from the flat peak portion to the hem (bottom), the coal pile 4 is cut to the minimum thickness dimension H1, and the cut coal is transported to the boiler 3.

That is, in the cutting, not only the sub-bituminous coal of the main body layer 42 but also the region thicker than the minimum thickness dimension H1 (the region of H2 to H1) that remains as the bottom layer 40 without cutting among the bituminous coal of the lowermost layer 41. Bituminous coal is being harvested. Since there is a high possibility that subbituminous coal will be mixed into the area to be cut in the lowest layer 41 when the main body layer 42 is piled up, the minimum height remaining without cutting by cutting including this area. The bottom layer 40 having a dimension H1 (for example, 0.5 m) does not contain subbituminous coal, whereby spontaneous combustion by subbituminous coal having high pyrophoricity can be suppressed.

note that. As a general rule, the main body layer 42 of subbituminous coal is not continuously piled up in the same area of the work space 16, but when the main body layer 42 of subbituminous coal is continuously piled up, the worker is the main body layer made of bituminous coal. After cutting, for example, the bottom layer 41 having a height of 1.0 m is formed, subbituminous coal is piled up in a smaller amount than the above to form the main body layer 42. Next, the operator cuts the main body layer 42 so that the thickness of the lowermost layer 41 is, for example, 0.8 m, and stacks subbituminous coal on the lowermost layer 41 to form the main body layer 42. Next, the worker cuts the coal pile 4 until the minimum thickness dimension is, for example, 0.5 m.

As described above, in the present embodiment, spontaneous combustion due to a highly spontaneously ignitable raw material can be suppressed.

The present invention is not limited to the above embodiment, and various modifications can be made.

For example, in the present embodiment, the configuration in which the lowermost layer 41 thicker than the minimum thickness dimension H1 is formed by cutting the coal pile 4 is exemplified. However, the tip of the stacker 5 is moved to a position at the height of the lowermost layer 41 of the coal pile 4 to be formed, and the arm 53 is rotated around the rotation shaft 51 while driving the boom conveyor 530 from this position. It may be moved and a pile of bituminous coal may be piled up in the work space 16 to form the bottom layer 41 of the coal pile 4 made of bituminous coal in a trapezoidal shape. In short, the structure may be such that the main body layer 42 of the raw material having high pyrophoricity is formed on the lowermost layer 41 formed to be thicker than the minimum thickness dimension H1.

Further, in the present embodiment, the case where the top layer 41 is cut after being formed has been described, but the present invention is not limited to this, and the top may be formed in a top surface shape when the bottom layer 41 is piled up. It is not necessary to include the step of forming the top surface on the top of the bottom layer 41.

Further, in the present embodiment, the case where the bottom layer 41 is piled up in one step has been described, but the present invention is not limited to this, and the bottom layer 41 may be piled up in a plurality of times.

Further, in the present embodiment, the case where the main body layer 42 is piled up in one step has been described, but the present invention is not limited to this, and the main body layer 42 may be piled up in a plurality of times.

Further, in the present embodiment, the upper surface of the lowermost layer 41 has been described as a flat surface, but the present invention is not limited to this, and a curved surface, a mountain-shaped surface, or a wavy surface may be used.

Further, in the present embodiment, the top surface of the mountaintop of the main body layer 42 has been described as a flat surface, but the present invention is not limited to this, and a curved surface, a mountain-shaped surface, or a wave-shaped surface may be used.

Further, in the present embodiment, coal used as a fuel for the boiler 3 is exemplified as a raw material to be stored in the storage area 1. However, it may be an ore or other pyrophoric raw material used as fuel for a steel mill blast furnace.

Further, in the present embodiment, the use of the stacker 5 and the reclaimer 6 is exemplified as a cargo handling and transporting machine for loading and reaping coal. However, a bulldozer or excavator may be used.

1 ... storage area, 10 ... carry-in conveyor, 11 ... carry-out conveyor, 12 ... first rail, 13 ... second rail, 14 ... first relay conveyor, 15 ... second relay conveyor, 16 ... work space, 2 ... Transport ship, 3 ... Boiler, 4 ... Coal pile, 40 ... Bottom layer, 41 ... Bottom layer, 42 ... Main body layer, 5 ... Stacker, 50 ... Cart, 51 ... Rotating shaft, 52 ... Aircraft, 53 ... Arm , 530 ... Boom conveyor, 54 ... Drive operation unit, 6 ... Reclaimer, 60 ... Cart, 61 ... Rotating shaft, 63 ... Arm, 630 ... Boom conveyor, 64 ... Drive operation unit, 65 ... Bucket wheel, H1 ... Coal pile Minimum thickness dimension, H2 ... height of the bottom layer of the coal mine, H3 ... height of the coal mine formed in a mountain shape, H4 ... height of the trapezoidal coal mine

Claims (2)

The bottom layer where the raw material pile is not cut on the ground of the storage area where the work of stacking the pyrophoric raw materials and storing them as the raw material pile and cutting the raw material from the raw material pile and transporting it to the raw material combustion facility is performed. A lowermost layer thicker than the minimum thickness dimension of the raw material pile for defining is formed, and a main body layer is formed by stacking raw materials having higher pyrophoricity than the raw material of the lowest layer on the lowermost layer. A raw material storage method characterized by forming a raw material pile by doing so. The raw material storage method according to claim 1, wherein a raw material mountain is formed by cutting a mountaintop portion of the main body layer after forming the main body layer.

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