APPARATUS FOR PREVENTING SPONTANEOUS IGNITION OF TRANSFERRED COAL IN APPARATUS FOR DRYING COAL USING REHEAT STEAM

Abstract

The present invention relates to an apparatus for preventing, in a multi-stage dryer for drying coal using reheat steam, spontaneous ignition caused by oxidation of coal when coal is transferred to the multi-stage dryer from a fixed quantity coal supplier by way of a pulverizer. The present invention relates to an apparatus for drying coal using reheat steam, the apparatus being configured so that coal which has been dried primarily in a first coal dryer is inputted into a second coal dryer and thus is secondarily dried, wherein reheat steam generated from a reheater is supplied through a reheat steam supply pipe; a nitrogen supplier supplies nitrogen through a nitrogen supply pipe; saturated steam generated from a saturated steam generator is supplied through a saturated steam supply pipe; the reheat steam supply pipe, the nitrogen supplier, and the saturated steam supply pipe are connected to a 4-way valve; and the 4-way valve supplies nitrogen and saturated steam, or nitrogen or saturated steam, along with reheat steam, to first to fourth steam chambers through the steam supply pipe, and injects steam into coal which is transferred to a first transfer plate and a second transfer plate so that spontaneous ignition of coal is prevented in the course of drying and transferring coal.

Claims

1. An apparatus for preventing spontaneous ignition of transferred coal in an apparatus for drying coal using reheat steam, the apparatus comprising: a first coal dryer in which a pair of first drive sprockets and a pair of first driven sprockets are spaced apart from each other at a predetermined distance to be fastened to first chains, respectively, a plurality of transfer plates is hinge-coupled between the first chains, a pair of first guide rails horizontally supporting the first transfer plate is installed below an upper second chain connected between the first drive sprocket and the first driven sprocket, a pair of second guide rails horizontally supporting the first transfer plate is installed below a lower first chain connected between the first drive sprocket and the first driven sprocket, a first steam chamber injecting reheat steam supplied from a reheater is installed below the upper first chain, a second steam chamber injecting reheat steam supplied from the reheater is installed below the lower first chain, a first exhaust gas chamber collecting exhaust gas is installed on the upper first chain, and a second exhaust gas chamber collecting exhaust gas is installed on the lower first chain; and a second coal dryer in which a pair of second drive sprockets and a pair of second driven sprockets are spaced apart from each other at a predetermined distance to be fastened to second chains, respectively, a plurality of transfer plates is hinge-coupled between the second chains, a pair of second guide rails horizontally supporting the second transfer plate is installed below an upper second chain connected between the second drive sprocket and the second driven sprocket, a pair of second guide rails horizontally supporting the second transfer plate is installed below a lower second chain connected between the second drive sprocket and the second driven sprocket, a third steam chamber injecting reheat steam supplied from the reheater is installed below the upper second chain, a fourth steam chamber injecting reheat steam supplied from the reheater is installed below the lower second chain, a third exhaust gas chamber collecting exhaust gas is installed on the upper second chain, and a fourth exhaust gas chamber collecting exhaust gas is installed on the lower second chain, wherein in the apparatus for drying coal using reheat steam, the apparatus being configured so that coal which has been dried primarily in the first coal dryer is inputted into the second coal dryer and thus is secondarily dried, reheat steam generated from a reheater is supplied through a reheat steam supply pipe, a nitrogen supplier supplies nitrogen through a nitrogen supply pipe, saturated steam generated from a saturated steam generator is supplied through a saturated steam supply pipe, and the reheat steam supply pipe, the nitrogen supplier, and the saturated steam supply pipe are connected to a 4-way valve, and the 4-way valve supplies nitrogen and saturated steam, or nitrogen or saturated steam, along with reheat steam, to first to fourth steam chambers through the steam supply pipe, and injects steam into coal which is transferred to the first transfer plate and the second transfer plate so that spontaneous ignition of coal is prevented in the course of drying and transferring coal.

2. The apparatus of claim 1, wherein the 4-way valve supplies reheat steam and nitrogen at a predetermined ratio, reheat steam and saturated steam at a predetermined ratio, or reheat steam, nitrogen and saturated steam at a predetermined ratio by an automatic or manual operation.

3. The apparatus of claim 1, wherein the nitrogen supplier supplies nitrogen through a second nitrogen supply pipe, the saturated steam generated from the saturated steam generator is supplied through a second saturated steam supply pipe, the second nitrogen supply pipe and the second saturated steam supply pipe are connected to a 3-way valve, and the 3-way valve supplies nitrogen and saturated steam, or nitrogen or saturated steam to a plurality of injection nozzles through a gas supply pipe, and injects the steam into coal which is transferred to the first transfer plate and the second transfer plate so that spontaneous ignition of coal is prevented in the course of drying and transferring coal.

4. The apparatus of claim 3, wherein the 3-way valve supplies nitrogen and saturated steam at a predetermined ratio, or supplies nitrogen or saturated steam at a predetermined ratio by an automatic or manual operation.

5. The apparatus of claim 3, wherein the injection nozzles are installed at the front side and rear side of the first exhaust gas chamber to the fourth exhaust gas chamber, respectively.

6. The apparatus of claim 1, wherein first transfer rollers are hinge-coupled between two-side centers of the first transfer plate and the first chains, respectively, at left and right sides of the first transfer roller, first auxiliary rollers are hinge-coupled with the sides of the first transfer plate, respectively, second transfer rollers are hinge-coupled between two-side centers of the second transfer plate and the second chains, respectively, at left and right sides of the second transfer roller, second auxiliary rollers are hinge-coupled with the sides of the second transfer plate, respectively, a first guide bar rotating and up-supporting the lower first transfer plate separated from the second guide rail in one direction is installed from the top to the bottom of the first drive sprocket along the side, a second guide bar rotating and down-supporting the upper first transfer plate separated from the first guide rail in one direction is installed from the bottom to the top of the second driven sprocket along the side, a third guide bar rotating and up-supporting the lower second transfer plate separated from the fourth guide rail in one direction is installed from the top to the bottom of the second drive sprocket along the side, a fourth guide bar rotating and down-supporting the upper second transfer plate separated from the third guide rail in one direction is installed from the bottom to the top of the second driven sprocket along the side, and a fixed quantity coal supplier supplies a predetermined amount of coal on the surface facing the top of the first transfer plate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a block diagram illustrating an apparatus for drying coal using reheat steam including an apparatus for preventing spontaneous ignition of transferred coal according to the present invention.

[0024] FIG. 2 is a configuration diagram illustrating a front side of the apparatus for drying coal using reheat steam, as a first embodiment of the present invention.

[0025] FIG. 3 is a configuration diagram illustrating a side of the apparatus for drying coal using reheat steam, as the first embodiment of the present invention.

[0026] FIGS. 4 and 5 are block diagrams illustrating the apparatus for preventing spontaneous ignition of transferred coal in the apparatus for drying coal using reheat steam according to the present invention.

[0027] FIG. 6 is a perspective view illustrating a main part installed with the apparatus for preventing spontaneous ignition of transferred coal in the apparatus for drying coal using reheat steam according to the present invention.

[0028] FIG. 7 is a configuration diagram illustrating a front side of the apparatus for drying coal using reheat steam, as a second embodiment of the present invention.

[0029] FIG. 8 is a perspective view illustrating a main part installed with the apparatus for preventing spontaneous ignition of transferred coal in the apparatus for drying coal using reheat steam according to the present invention.

[0030] FIG. 9 is a perspective view illustrating a main part in the apparatus for drying coal using reheat steam according to the present invention.

[0031] FIG. 10 is a separated perspective view illustrating a main part of a transfer device in the apparatus for drying coal using reheat steam according to the present invention.

[0032] FIGS. 11 and 12 are cross-sectional views illustrating an operation of the transfer device in the apparatus for drying coal using reheat steam according to the present invention, respectively.

BEST MODE FOR THE INVENTION

[0033] Exemplary embodiments of the present invention will be described below in more detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present invention.

[0034] Hereinafter, an apparatus for preventing spontaneous ignition of transferred coal for drying in an apparatus for drying coal using reheat steam will be described in detail with reference to the accompanying drawings.

[0035] The apparatus for preventing spontaneous ignition of transferred coal of the present invention is installed in the apparatus for drying coal, and a fixed quantity coal supplier in the apparatus for drying coal mixes and injects nitrogen containing hot reheat steam and saturated steam at a predetermined ratio while supplying and transferring coal to a transfer device such as a conveyor or a transfer plate, mixes and injects nitrogen containing reheat steam at a predetermined ratio, or mixes and injects saturated steam containing reheat steam at a predetermined ratio to prevent spontaneous ignition of coal dried when drying the coal. Further, while the coal is transferred to the transfer device such as the conveyor or the transfer plate in the apparatus for drying coal, nitrogen and/or saturated steam is mixed at a predetermined ratio and injected on the coal surface to prevent spontaneous ignition of coal.

[0036] In FIG. 1, a coal yard 200 keeps and stores coal used as boiler fuel of a thermal power plant. The coal contains surface moisture and internal moisture. Further, the coal stored in the coal yard 200 is sprayed with water to prevent scattering of coal dust. The coal stored in the coal yard 200 is transferred to the apparatus for drying coal 100 through a transfer means such as a conveyor system. In this case, the coal in the coal yard 200 without removing the moisture may be transferred and stored to a coal supply tank 300 for dying connected with the apparatus for drying coal. In addition, the coal stored in the coal supply tank 300 is supplied to the apparatus for drying coal 100 from the fixed quantity coal supplier 400 with a predetermined amount. The apparatus for drying coal 100 includes a first coal dryer 110 installed in multiple layers and a third coal dryer 170 for naturally drying the coal discharged through a second coal dryer 140. The first coal dryer 110 and the second coal dryer 140 have substantially the same structure. The coal naturally dried through the third coal dryer 170 is stored in a dried coal reservoir 600 and then supplied as boiler fuel of a thermal power plant 700.

[0037] Further, nitrogen supplied from a nitrogen supplier 800 and saturated steam generated in a saturated steam generator 900 are supplied to the first coal dryer 110 and the second coal drier 140 of the apparatus for drying coal 100.

[0038] FIGS. 2 and 3 illustrate an example of the apparatus for drying coal 100 installed with the apparatus for preventing spontaneous ignition of transferred coal according to the present invention. The apparatus for drying coal 100 includes a multi-stage dryer, that is, the first coal dryer 110 drying the coal input from the fixed quantity coal supplier 400, the second coal dryer 140 secondarily drying the coal dried in the first coal dryer, and the third coal dryer 170 naturally drying the coal dried in the second coal dryer and then supplying the dried coal to a dried coal reservoir 50.

[0039] In the first coal dryer 110, a pair of first drive sprockets 111 and a pair of first driven sprockets 112 are spaced apart from each other at a predetermined distance to be fastened to first chains 113, respectively, a plurality of transfer plates 114 is hinge-coupled between the first chains 113, a pair of first guide rails 115 horizontally supporting the first transfer plate 114 is installed below an upper second chain 143 connected between the first drive sprocket 111 and the first driven sprocket 112, a pair of second guide rails 116 horizontally supporting the first transfer plate 114 is installed below a lower first chain 113 connected between the first drive sprocket 111 and the first driven sprocket 112, a first steam chamber 120 injecting reheat steam supplied from a reheater 500 is installed below the upper first chain 113, a second steam chamber 123 injecting reheat steam supplied from the reheater 500 is installed below the lower first chain 113, a first exhaust gas chamber 124 collecting exhaust gas is installed on the upper first chain 113, and a second exhaust gas chamber 126 collecting exhaust gas is installed on the lower first chain 113.

[0040] In addition, in the second coal dryer 140, a pair of second drive sprockets 141 and a pair of second driven sprockets 142 are spaced apart from each other at a predetermined distance to be fastened to second chains 143, respectively, a plurality of transfer plates 144 is hinge-coupled between the second chains 143, a pair of second guide rails 145 horizontally supporting the second transfer plate 144 is installed below an upper second chain 143 connected between the second drive sprocket 141 and the second driven sprocket 142, a pair of second guide rails 146 horizontally supporting the second transfer plate 144 is installed below a lower second chain 143 connected between the second drive sprocket 141 and the second driven sprocket 142, a third steam chamber 150 injecting reheat steam supplied from the reheater 500 is installed below the upper second chain 143, a fourth steam chamber 153 injecting reheat steam supplied from the reheater 500 is installed below the lower second chain 143, a third exhaust gas chamber 154 collecting exhaust gas is installed on the upper second chain 143, and a fourth exhaust gas chamber 156 collecting exhaust gas is installed on the lower second chain 143.

[0041] In addition, in the first transfer plate 114, a plurality of through-holes 114a is formed so that the reheat steam injected from the first steam chamber 120 and the second steam chamber 123 passes through the first transfer plate 114 to contact coal particles. At upper left and right sides of the first transfer plate 114, guards 114b having predetermined heights are installed to prevent the input coal pile from flowing in a left or right direction of the first transfer plate 114. The guard 114b has a shape that is narrow at the top and widened at the bottom as a substantially trapezoidal shape. Accordingly, the top of the guard 114b of the first transfer plate 114 is overlapped with an adjacent guard 114b. In this case, the guard 114b of the first transfer plate 114 may be installed in a substantially zigzag direction with the adjacent guard 114b. Further, at lower left and right sides of the first transfer plate 114, shield plates 114c are installed to prevent the reheat steam injected from the first steam chamber 120 and the second steam chamber 123 from being lost when injected to left and right sides of each of the first steam chamber 120 and the second steam chamber 123.

[0042] In addition, in the second transfer plate 144, a plurality of through-holes 144a is formed so that the reheat steam injected from the third steam chamber 150 and the fourth steam chamber 153 passes through the second transfer plate 144 to contact coal particles. At upper left and right sides of the second transfer plate 144, guards 144b having a predetermined height are installed to prevent the input coal pile from flowing in a left or right direction of the second transfer plate 144. The guard 144b has a shape that is narrow at the top and widened at the bottom as a substantially trapezoidal shape. Accordingly, the top of the guard 144b of the second transfer plate 144 is overlapped with an adjacent guard 144b. In this case, the guard 144b of the second transfer plate 144 may be installed in a substantially zigzag direction with the adjacent guard 144b. Further, at lower left and right sides of the second transfer plate 144, shield plates 144c are installed to prevent the reheat steam injected from the third steam chamber 150 and the fourth steam chamber 153 from being lost when injected to left and right sides of each of the third steam chamber 150 and the fourth steam chamber 153.

[0043] In FIG. 4, in each of the first steam chamber 120 and the second steam chamber 123 installed in the first transfer plate 114 of the first coal dryer 110, a steam supply pipe 121 is installed, and in each of the third steam chamber 150 and the fourth steam chamber 153 installed in the second transfer plate 144 of the second coal dryer 140, a steam supply pipe 151 is installed. In each of the steam supply pipes 121 and 151, a 4-way valve 1000 is installed. The 4-way valve 1000 controls the flow of fluid in four directions.

[0044] In FIG. 6, in the 4-way valve 1000, a reheat steam supply pipe 501 supplying the reheat steam generated in the reheater 500 is installed. The reheater 500 receives exhaust gas discharged from the first to fourth exhaust gas chambers 124, 126, 154, and 156 corresponding to the first to fourth steam chambers 120, 123, 150, and 153 to regenerate and supply the received gas as reheat steam. In the 4-way valve 1000, a nitrogen supply pipe 801 supplying nitrogen from a nitrogen supplier 800 is installed. The nitrogen supplier 800 may include a device of supplying nitrogen from a storage tank that stores liquefied nitrogen or collecting and supplying nitrogen in air. Further, in the 4-way valve 1000, a saturated steam supply pipe 901 supplying saturated steam from a saturated steam generator 900 is installed. The saturated steam generated from saturated steam generator 900 is hot and humid steam containing more than a predetermined amount of moisture and the reheat steam generated from the reheater 500 is hot and dried steam containing more than a predetermined amount of moisture.

[0045] Accordingly, in the 4-way valve 1000, the reheat steam, nitrogen, and the saturated steam received from the reheater 500, the nitrogen supplier 800, and the saturated steam generator 900 through the reheat steam supply pipe 501, the nitrogen supply pipe 801, and the saturated steam supply pipe 901 are supplied to the corresponding steam chambers 120, 123, 150, and 153 through the steam supply pipes 121 and 151, respectively. The 4-way valve 1000 may supply only any one of the reheat steam, nitrogen, and the saturated steam to the steam chambers 120, 123, 150, and 153 through the steam supply pipes 121 and 151 according to a manual or automatic operation of the valve. Further, the 4-way valve 1000 may supply nitrogen or saturated steam containing reheat steam to the steam chambers 120, 123, 150, and 153 through the steam supply pipes 121 and 151 at a predetermined ratio according to a manual or automatic operation of the valve. Preferably, the 4-way valve 1000 may be operated to supply reheat steam and nitrogen, reheat steam and saturated steam, or reheat steam, nitrogen, and saturated steam at a predetermined ratio. The reason is that in the case where transferred coal loaded on the transfer plate is dried with hot and dried reheat steam, when moisture contained in the inside and on the surface of the coal is fully evaporated, a possibility that spontaneous ignition occurs while the coal is transferred may be increased.

[0046] Therefore, the apparatus for preventing spontaneous ignition of transferred coal in the apparatus for drying coal injects nitrogen mixed in the reheat steam with a predetermined amount to the transferred coal by the operation of the 4-way valve 1000 installed in the steam supply pipes 121 and 151 connected to the steam chambers 120, 123, 150, and 153 to dry the coal and prevent oxygen from being in contact with the coal particles, thereby preventing oxidation of the coal to prevent spontaneous ignition.

[0047] Further, saturated steam mixed in the reheat steam with a predetermined amount is injected to the transferred coal by the operation of the 4-way valve 1000 installed in the steam supply pipes 121 and 151 connected to the steam chambers 120, 123, 150, and 153 to dry the coal and saturated steam containing a predetermined amount of moisture is injected to the coal to provide a minimal amount of moisture without causing spontaneous ignition to the coal particles.

[0048] Further, nitrogen and saturated steam mixed in the reheat steam with a predetermined amount is injected to the coal by the operation of the 4-way valve 1000 installed in the steam supply pipes 121 and 151 connected to the steam chambers 120, 123, 150, and 153 to prevent oxygen from being in contact with the coal particles and provide a minimal amount of moisture without causing spontaneous ignition to the coal particles.

[0049] In FIG. 5, a second nitrogen supply pipe 802 supplying nitrogen is installed in the nitrogen supplier 800 and a second saturated steam supply pipe 902 supplying saturated steam is installed in the saturated steam generator 900. In addition, the second nitrogen supply pipe 802 and the second saturated steam supply pipe 902 are connected to a 3-way valve 1000. The 3-way valve 1000 supplies nitrogen and saturated steam, nitrogen or saturated steam to a plurality of injection nozzles 1102 through a gas supply pipe 1101.

[0050] The 3-way valve 1000 supplies nitrogen and saturated steam at a predetermined ratio by an automatic or manual operation or supplies nitrogen or saturated steam at a predetermined ratio.

[0051] Further, the injection nozzles 1102 are installed at the front side and the rear side of the first to fourth flue gas chambers 124, 126, 154, and 156 to inject nitrogen and/or saturated steam on the coal surface before or after drying the reheat steam on the first transfer plate 114 and the second transfer plate 144, thereby preventing spontaneous ignition of coal.

[0052] As another example of the present invention, in FIGS. 7 to 12, an apparatus for preventing spontaneous ignition of transferred coal in an apparatus for drying coal using reheat steam is applied.

[0053] In FIG. 10, a second transfer roller 135 is hinge-coupled between two-side centers of the second transfer plate 144 and the second chains 113. That is, the second transfer roller 135 is hinge-coupled between the lateral center of the second transfer plate 144 and the second chain 143. In addition, at left and right sides of the second transfer roller 135, second auxiliary rollers 136 are hinge-coupled with the sides of the second transfer plate 144, respectively. The second auxiliary rollers 136 are hinge-coupled with the sides of the second transfer plate 144, that is, the left side and the right side.

[0054] Further, a groove 145a and a groove 146a guiding rotation of the second transfer roller 135 and the second auxiliary roller 136 are formed on the surfaces of the third guide rail 145 and the fourth guide rail 146, respectively. Accordingly, the second transfer roller 135 and the second auxiliary roller 136 hinge-coupled with the second transfer plate 144 is transferred along the groove 145a formed on the surface of the third guide rail 145 and the groove 146a formed on the surface of the fourth guide rail 146.

[0055] Meanwhile, in FIGS. 11 and 12, a third guide bar 157 rotating and up-supporting the lower second transfer plate 144 separated from the fourth guide rail 146 in one direction is installed from the top to the bottom of the second drive sprocket 141 along the side. A third trigger 157a is coupled to the end of a third guide bar 157 and the third trigger 157a is constituted by an axial rotating roller. The third trigger 157a is installed at a position which is in contact with a lower side of the upper second transfer plate 144.

[0056] Further, a fourth guide bar 159 rotating and down-supporting the upper second transfer plate 144 separated from the third guide rail 145 is installed from the bottom to the top of the second driven sprocket 142 along the side. A fourth trigger 159a is coupled to the end of a fourth guide bar 159 and the fourth trigger 159a is constituted by an axial rotating roller. The fourth trigger 159a is installed at a position which is in contact with a planar side of the lower second transfer plate 144.

[0057] In addition, in the first transfer plate 114, a plurality of through-holes 114a is formed so that the reheat steam injected from the first steam chamber 120 and the second steam chamber 123 passes through the first transfer plate 114 to contact coal particles. At upper left and right sides of the first transfer plate 114, a guard 114b having a predetermined height is installed to prevent the input coal pile from flowing in a left or right direction of the first transfer plate 114. The guard 114b has a shape that is narrow at the top and widened at the bottom as a substantially trapezoidal shape. Accordingly, the top of the guard 114b of the first transfer plate 114 is overlapped with an adjacent guard 114b. In this case, the guard 114b of the first transfer plate 114 is installed in a substantially zigzag direction with the adjacent guard 114b. Further, at lower left and right sides of the first transfer plate 114, shield plates 114c are installed to prevent the reheat steam injected from the first steam chamber 120 and the second steam chamber 123 from being lost when injected to left and right sides of each of the first steam chamber 120 and the second steam chamber 123.

[0058] In addition, in the second transfer plate 144, a plurality of through-holes 144a is formed so that the reheat steam injected from the third steam chamber 150 and the fourth steam chamber 153 passes through the second transfer plate 144 to contact coal particles. At upper left and right sides of the second transfer plate 144, guards 144b having a predetermined height are installed to prevent the input coal pile from flowing in a left or right direction of the second transfer plate 144. The guard 144b has a shape that is narrow at the top and widened at the bottom as a substantially trapezoidal shape. Accordingly, the top of the guard 144b of the second transfer plate 144 is overlapped with an adjacent guard 144b. In this case, the guard 144b of the second transfer plate 144 may be installed in a substantially zigzag direction with the adjacent guard 144b. Further, at lower left and right sides of the second transfer plate 144, shield plates 144c are installed to prevent the reheat steam injected from the third steam chamber 150 and the fourth steam chamber 153 from being lost when injected to left and right sides of each of the third steam chamber 150 and the fourth steam chamber 153.

[0059] In addition, in FIG. 12A, the upper first transfer plate 114 is transferred to the end of the first guide rail 115 by rotating the first driven sprocket 112. In FIG. 12B, while the lower left side of the upper first transfer plate 114 deviates from the end of the first guide rail 115, the lower right side of the upper first transfer plate 114 is in contact with the second trigger 119a of the second guide bar 119. In this case, in the upper first chain 113, the upper first transfer plate 114 hinge-coupled to the first transfer roller 133 is separated from the first guide rail 115 and simultaneously rotates in a left direction of the first transfer roller 133 as an axis to drop down the loaded coal pile. In addition, in FIG. 12C, the bottom of the upper first transfer plate 114 moves downward along the second trigger 119a. In FIG. 12D, the upper first transfer plate 114 is maintained in a substantially vertical state and moves without pivoting along a rotation radius of the first drive sprocket 112 while the bottom contacts the second guide bar 119. In FIG. 12E, while the upper first transfer plate 114 transferred downward moves up to the second guide rail 116, the coal pile dropped down from the first transfer plate along the lower first transfer plate 114 is loaded and transferred. In addition, the coal pile loaded on the lower first transfer plate 114 is transferred and dried by the reheat steam.

[0060] Next, in FIG. 11A, the lower first transfer plate 114 is transferred to the end of the second guide rail 116 by rotating the first drive sprocket 111. In FIG. 11B, while the lower right side of the lower first transfer plate 114 deviates from the end of the second guide rail 116, the planar left side of the lower first transfer plate 114 is in contact with the first trigger 117a of the first guide bar 117. In this case, in the lower first chain 113, the lower first transfer plate 114 hinge-coupled to the first transfer roller 133 is separated from the second guide rail 116 and simultaneously rotates in a left direction of the first transfer roller 133 as an axis to drop down the loaded coal pile. In addition, in FIG. 11C, the plane of the upper first transfer plate 114 moves upward along the first trigger 117a. In FIG. 11D, the lower first transfer plate 114 is maintained in a substantially vertical state and moves without pivoting along a rotation radius of the first drive sprocket 111 while the plane contacts the first guide bar 117. In FIG. 11E, while the lower first transfer plate 114 transferred upward moves up to the first guide rail 115, the coal pile input from the fixed quantity coal supplier 400 with a predetermined amount along the upper first transfer plate 114 is loaded and transferred. In addition, the coal pile loaded on the upper first transfer plate 114 is transferred and dried by the reheat steam. The coal pile dropped from the lower first transfer plate 114 is discharged to an outlet 131 along a first slope 139.

[0061] Further, the coal pile dropped from the first coal dryer 110 to the outlet 131 is input to an inlet 160 of the second coal dryer 140, input on the surface of the second transfer plate 144 of the second coal dryer 140, and then transferred. In addition, the coal pile loaded on the upper second transfer plate 144 is transferred and dried by the reheat steam.

[0062] The transfer process of coal in the second coal dryer 140 is the same as the transfer process of the first coal dryer 110. In addition, the coal pile dropped from the lower second transfer plate 144 is discharged to an outlet 161 along a second slope 149. In addition, the coal pile dropped from the second coal dryer 140 to the outlet 161 is naturally dried while supplied and transferred to the third coal dryer 170.

[0063] In the present invention, the steam supply pipe 121 supplying hot reheat steam generated from the reheater 500 is connected to one side of the first steam chamber 120 and the second steam chamber 123, and the steam supply pipe 151 supplying hot reheat steam generated from the reheater 500 is connected to one side of the third steam chamber 150 and the fourth steam chamber 153. In addition, a perforated plate 10 for first steam distribution through-formed with a plurality of first steam injection holes 11 is installed on the inside of each of the first steam chamber 120, the second steam chamber 123, the third steam chamber 150, and the fourth steam chamber 153. In each of the first steam chamber 120 to the fourth steam chamber 153, the reheat stream having uniform pressure is injected through the first steam injection holes 11.

[0064] In FIG. 4, in each of the first steam chamber 120 and the second steam chamber 123 installed in the first transfer plate 114 of the first coal dryer 110, a steam supply pipe 121 is installed, and in each of the third steam chamber 150 and the fourth steam chamber 153 installed in the second transfer plate 144 of the second coal dryer 140, a steam supply pipe 151 is installed. In each of the steam supply pipes 121 and 151, a 4-way valve 1000 is installed. The 4-way valve 1000 controls the flow of fluid in four directions.

[0065] Further, in the 4-way valve 1000, a reheat steam supply pipe 501 supplying the reheat steam generated in the reheater 500 is installed. The reheater 500 receives exhaust gas discharged from the first to fourth exhaust gas chambers 124, 126, 154, and 156 corresponding to the first to fourth steam chambers 120, 123, 150, and 153 to regenerate and supply the received gas as reheat steam. In the 4-way valve 1000, a nitrogen supply pipe 801 supplying nitrogen from a nitrogen supplier 800 is installed. The nitrogen supplier 800 may include a device of supplying nitrogen from a storage tank that stores liquefied nitrogen or collecting and supplying nitrogen in air. Further, in the 4-way valve 1000, a saturated steam supply pipe 901 supplying saturated steam from a saturated steam generator 900 is installed. The saturated steam generated from saturated steam generator 900 is hot and humid steam containing more than a predetermined amount of moisture and the reheat steam generated from the reheater 500 is hot and dried steam containing more than a predetermined amount of moisture.

[0066] Accordingly, in the 4-way valve 1000, the reheat steam, nitrogen, and the saturated steam received from the reheater 500, the nitrogen supplier 800, and the saturated steam generator 900 through the reheat steam supply pipe 501, the nitrogen supply pipe 801, and the saturated steam supply pipe 901 are supplied to the corresponding steam chambers 120, 123, 150, and 153 through the steam supply pipes 121 and 151, respectively. The 4-way valve 1000 may supply only any one of the reheat steam, nitrogen, and the saturated steam to the steam chambers 120, 123, 150, and 153 through the steam supply pipes 121 and 151 according to a manual or automatic operation of the valve. Further, the 4-way valve 1000 may supply nitrogen or saturated steam containing reheat steam to the steam chambers 120, 123, 150, and 153 through the steam supply pipes 121 and 151 at a predetermined ratio according to a manual or automatic operation of the valve. Preferably, the 4-way valve 1000 may be operated to supply reheat steam and nitrogen, reheat steam and saturated steam, or reheat steam, nitrogen, and saturated steam at a predetermined ratio. The reason is that in the case where transferred coal loaded on the transfer plate is dried with hot and dried reheat steam, when moisture contained in the inside and on the surface of the coal is fully evaporated, a possibility that spontaneous ignition occurs while the coal is transferred may be increased.

[0067] Therefore, the apparatus for preventing spontaneous ignition of transferred coal in the apparatus for drying coal injects nitrogen mixed in the reheat steam with a predetermined amount to the transferred coal by the operation of the 4-way valve 1000 installed in the steam supply pipes 121 and 151 connected to the steam chambers 120, 123, 150, and 153 to dry the coal and prevent oxygen from being in contact with the coal particles, thereby preventing oxidation of the coal to prevent spontaneous ignition.

[0068] Further, saturated steam mixed in the reheat steam with a predetermined amount is injected to the transferred coal by the operation of the 4-way valve 1000 installed in the steam supply pipes 121 and 151 connected to the steam chambers 120, 123, 150, and 153 to dry the coal and saturated steam containing a predetermined amount of moisture is injected to the coal to provide a minimal amount of moisture without causing spontaneous ignition to the coal particles.

[0069] Further, nitrogen and saturated steam mixed in the reheat steam with a predetermined amount is injected to the coal by the operation of the 4-way valve 1000 installed in the steam supply pipes 121 and 151 connected to the steam chambers 120, 123, 150, and 153 to prevent oxygen from being in contact with the coal particles and provide a minimal amount of moisture without causing spontaneous ignition to the coal particles.

[0070] Accordingly, the apparatus for preventing spontaneous ignition of transferred coal in the apparatus for drying coal has advantages of drying the coal and preventing spontaneous ignition by supplying reheat stream and nitrogen or saturated steam to the steam chambers 120 and 123 installed below the first transfer plate 114 and the steam chambers 150 and 153 installed below the second transfer plate 144 with a predetermined ratio to inject the reheat stream and nitrogen or saturated steam to the transferred coal on the corresponding plate, and reducing costs according to maintenance of the apparatus for drying coal as well as improving dry efficiency and preventing failure or malfunction of the apparatus for drying coal by spontaneous ignition which may be generated in the course of drying coal in the apparatus for drying coal by injecting nitrogen and saturated steam onto the coal surface transferred to the first transfer plate 114 and the second transfer plate 144 at a predetermined ratio.

[0071] While the present invention has been described with respect to the specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.

INDUSTRIAL AVAILABILITY

[0072] The present invention has industrial availability which can maximize usage of the apparatus for drying coal by preventing ignition or spontaneous ignition of coal that may be generated when the coal is dried or transferred in the apparatus for drying coal using reheat steam, prevent incomplete combustion of coal by removing moisture that remains at the inside and outside of the coal as used fuel of a thermal power plant, and improve stability of coal supply by improving a caloric value of coal and minimizing emission of pollutants, reducing spontaneous ignition rate according to reduction in moisture of the coal, and enhancing utilization of low-grade coal with low demand.