JP6926444B2 - Cooling system - Google Patents

Description

The present disclosure relates to a cooling device for cooling hydrous coal dried by heating.

Coal has more than three times the recoverable life of petroleum, and its reserves are not unevenly distributed compared to petroleum. Therefore, coal is expected as a natural resource that can be stably supplied for a long period of time. Coal is classified into peat, lignite, lignite, subbituminous coal, bituminous coal, semi-smokeless coal, and smokeless coal in ascending order of carbon content. Peat, sub-coal, brown coal, and sub-bituminous coal (hereinafter referred to as hydrous coal) have a higher water content (moisture content) than bituminous coal, semi-anthracite coal, and smokeless coal (hereinafter referred to as anthracite coal and the like).

Of the hydrous coal, lignite is said to account for half of the world's coal reserves, so effective use of lignite is being considered. However, as described above, hydrous coal such as lignite has a higher water content than anthracite coal and the like. Therefore, hydrous coal has a low calorific value per unit weight and low energy efficiency as a fuel with respect to transportation costs.

Therefore, a technique has been developed in which superheated steam is supplied to the hydrated coal to heat and dry the hydrated coal while flowing it (for example, Patent Document 1). Hydrous coal dried by heating (hereinafter, dried hydrous coal is referred to as "dry coal") may ignite when it comes into contact with the atmosphere at a high temperature (for example, about 80 ° C. to 150 ° C.). Therefore, in the technique of Patent Document 1, the dry coal is cooled by supplying a low-temperature inert gas from the bottom surface of the storage tank containing the high-temperature dry coal.

Japanese Unexamined Patent Publication No. 2013-173086

In the technique of Patent Document 1 described above, it is necessary to use a large amount of inert gas for cooling the dry coal. Therefore, there is a problem that the cost required for the inert gas is high.

In view of such a problem, the present disclosure aims to provide a cooling device capable of cooling dry coal at low cost.

In order to solve the above problems, the cooling device according to one aspect of the present disclosure is provided at an introduction port into which the hydrous coal dried by heating is introduced and below the introduction port, and the hydrous coal is discharged. Organic comprising a spray unit for spraying a solvent.

Further, the organic solvent sprayed by the spray unit is provided with a condensing unit that cools and condenses the vaporized gas by contacting with the dried hydrous coal, and the spray unit is generated by the condensing unit. The organic solvent may be sprayed onto the dried hydrous coal.

It is possible to cool dry coal at low cost.

It is a figure explaining the drying system. It is a figure explaining the cooling apparatus which concerns on 1st Embodiment. It is a figure explaining the cooling apparatus which concerns on 2nd Embodiment. It is a figure explaining free water and combined water.

An embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. The dimensions, materials, other specific numerical values, etc. shown in such an embodiment are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate description, and elements not directly related to the present disclosure are omitted from the illustration. do.

(Drying system 100)
FIG. 1 is a diagram illustrating a drying system 100. As shown in FIG. 1, the drying system 100 includes a drying device 110, a cooling device 120, and a storage unit 130, and dries the hydrous coal. Here, lignite will be described as an example of hydrous coal.

The drying device 110 dries the lignite BC by heating the lignite BC. The drying device 110 is, for example, a fluidized bed drying furnace, and includes a storage tank, a fluidized gas supply unit, and a heat transfer tube. The containment tank accommodates lignite BC. The fluidized gas supply unit supplies fluidized gas (for example, water vapor) from the lower part of the fluidized bed (containment tank). The heat transfer tube is arranged in a fluidized bed (containment tank), and a heat medium having a temperature higher than that of lignite BC passes through the heat transfer tube. Since various existing techniques can be applied to the technique for drying lignite BC, detailed description thereof will be omitted here.

The cooling device 120 cools the lignite BC (dried coal DC) dried by the drying device 110. The specific configuration of the cooling device 120 will be described in detail later.

The storage unit 130 stores the dry coal DC cooled by the cooling device 120. The dry coal DC stored in the storage unit 130 is supplied to a dry coal utilization facility such as a boiler.

Hereinafter, the cooling device 120 according to the present embodiment will be described in detail.

(Cooling device 120)
FIG. 2 is a diagram illustrating a cooling device 120 according to the first embodiment. As shown in FIG. 2, the cooling device 120 includes a main body unit 210, a first cooling unit 220, a spray unit 230, and a condensing unit 240. In FIG. 2, the gas flow is indicated by a broken line arrow, the liquid flow is indicated by a solid arrow, and the solid flow is indicated by a white arrow.

The main body 210 includes an upper part 212, a central part 214, and a lower part 216. The upper portion 212 has a conical shape, and the top portion is arranged vertically above. A pipe 212a is connected to the top of the upper 212. The brown coal BC (dry coal DC, for example, about 80 ° C. to 150 ° C.) dried by the drying device 110 is introduced into the main body 210 (upper part 212) through the pipe 212a.

Further, a disperser 212b is provided in the internal space of the upper part 212. The disperser 212b disperses the dry coal DC introduced through the pipe 212a. In the present embodiment, the disperser 212b is composed of a plurality of conical members 212ca and 212cc. The member 212ca arranged most vertically upward is arranged in the internal space of the upper part 212 so that the top surface faces the opening of the pipe 212a. Below the member 212ca, the member 212cc is arranged. The member 212cc is arranged so that the top thereof faces the lower end of the member 212ca.

Therefore, the dry coal DC introduced into the upper portion 212 through the pipe 212a is dropped and conveyed, collides with the top of the member 212ca, and is dispersed outward in the radial direction of the member 212ca. The dispersed dry coal DC flows down the outer wall surface of the member 212ca and is dropped and conveyed from the lower end. Then, the dry coal DC dropped and conveyed from the member 212ca collides with the top of the member 212cc and is dispersed outward in the radial direction of the member 212cc. The dispersed dry coal DC flows down the outer wall surface of the member 212 cc, and is dropped and conveyed from the lower end to the central portion 214.

The central portion 214 is a cylindrical tube continuous with the lower end of the upper portion 212, and is installed so that the central axis is along the vertical direction. The lower portion 216 has a conical shape and is continuous with the lower end of the central portion 214, and the upper portion is arranged vertically downward. A pipe 216a is connected to the top of the lower portion 216.

Therefore, the dry coal DC introduced into the upper part 212 through the pipe 212a falls (drops and is conveyed) in the central portion 214 and the lower portion 216, and is introduced into the storage portion 130 through the pipe 216a.

The first cooling unit 220 is composed of, for example, a water cooling device, and cools the main body unit 210. Therefore, the dry coal DC is cooled in the process of passing (falling) the dry coal DC through the main body 210.

The spray unit 230 sprays a liquid (for example, about room temperature (25 ° C.)) on the dry coal DC that passes (falls) through the main body 210. More specifically, in the present embodiment, the spray unit 230 includes a nozzle 232 and a pump 234. The nozzle 232 is arranged so that the opening faces the internal space of the main body 210. The pump 234 supplies the liquid generated by the recovery unit 242, which will be described later, to the nozzle 232. Then, the liquid is sprayed from the nozzle 232 into the main body 210.

As a result, the dry charcoal DC (about 80 ° C. to 150 ° C.) comes into contact with the liquid, and heat exchange is performed between the dry charcoal DC and the liquid. Here, the liquid sprayed by the spray unit 230 onto the dry coal DC is an organic solvent having a boiling point of 100 ° C. or lower (for example, methanol). Therefore, when the liquid comes into contact with the dry charcoal DC, the liquid vaporizes into a gas. That is, the latent heat of the liquid cools the dry charcoal DC. Further, when the gas and the dry coal DC come into contact with each other, the dry coal DC is cooled by the sensible heat of the gas.

In this way, the spray unit 230 can cool the dry coal DC by the latent heat and sensible heat of the liquid only by spraying the liquid having a boiling point of 100 ° C. or lower onto the dry coal DC. Therefore, the dry coal DC can be cooled with an extremely small amount of liquid as compared with the conventional technique of cooling only by the sensible heat of the inert gas. This makes it possible to cool the dry coal DC at low cost.

The dried coal DC cooled in this way (for example, about 50 ° C.) is introduced into the storage unit 130 and stored in the storage unit 130. The dry coal DC is exposed to room temperature (for example, 25 ° C.) while being stored in the storage unit 130. Therefore, the liquid (residual liquid) adhering to the dry coal DC is vaporized to become a gas.

Further, in the present embodiment, the spray unit 230 has the temperature of the dry charcoal DC introduced into the main body 210 (for example, about 80 ° C. to 150 ° C.) and the dry charcoal DC desired when discharged from the main body 210. The difference from the temperature (for example, about 50 ° C.) is sprayed with the minimum amount of liquid that can be endothermic by latent heat and sensible heat. As a result, only the minimum amount of liquid required for cooling the dry coal DC can be sprayed.

The condensing unit 240 includes a recovery unit 242 and a second cooling unit 244. The gas generated in the main body 210 and the gas generated in the storage 130 are introduced into the recovery unit 242. The second cooling unit 244 is composed of, for example, a pipe through which the refrigerant flows, and is arranged in the recovery unit 242. The second cooling unit 244 cools the gas and condenses it into a liquid by absorbing (endothermic) the heat of the gas in the flow process of the refrigerant. In this way, the liquid condensed in the condensing unit 240 is sprayed onto the dry coal DC by the spray unit 230.

The liquid can be reused by the configuration including the condensing unit 240. Therefore, it is possible to further cool the dry coal DC at low cost.

As described above, according to the cooling device 120 according to the present embodiment, the dry coal DC can be cooled at low cost with a simple configuration of simply spraying a liquid having a boiling point of 100 ° C. or lower onto the dry coal DC. It will be possible.

(Second embodiment: cooling device 320)
In the first embodiment, the cooling device 120 in which the dry coal DC is dropped and conveyed in the main body 210 has been described as an example. Therefore, the cooling device 120 can convey the dry coal DC without requiring power. However, the cooling device 120 may carry the dry coal DC in another configuration.

FIG. 3 is a diagram for explaining the cooling device 320 according to the second embodiment. As shown in FIG. 3, the cooling device 320 includes a main body portion 310, a spray portion 230, and a condensing portion 240. In FIG. 3, the gas flow is indicated by a broken line arrow, the liquid flow is indicated by a solid arrow, and the solid flow is indicated by a white arrow. Further, the components substantially the same as those of the cooling device 120 described above are designated by the same reference numerals, and the description thereof will be omitted.

The main body 310 includes an accommodating portion 312 and a transport portion 314. The accommodating portion 312 extends in the horizontal direction and has a hollow interior. The transport unit 314 is composed of, for example, a conveyor and is arranged on the bottom surface of the accommodating unit 312. The transport unit 314 transports the dry coal DC from one end side to the other end side of the accommodating unit 312. In the present embodiment, the dried charcoal DC dried by the drying device 110 is introduced to one end side of the transport unit 314.

The nozzle 232 of the spray unit 230 is arranged so that the opening faces the upper surface of the accommodating unit 312. Therefore, the liquid is sprayed in the process of transporting the dry coal DC by the transport unit 314. At this time, the dry charcoal DC (about 80 ° C. to 150 ° C.) comes into contact with the liquid, and heat exchange is performed between the dry charcoal DC and the liquid.

As described above, also in the present embodiment, the cooling device 320 can cool the dry coal DC at low cost by simply spraying a liquid having a boiling point of 100 ° C. or lower onto the dry coal DC. It becomes.

(Modification example)
In the above embodiment, the spray unit 230 has been described by taking as an example a configuration in which an organic solvent is sprayed as a liquid having a boiling point of 100 ° C. or lower. However, the spray unit 230 may spray water as long as it is a liquid having a boiling point of 100 ° C. or lower, not limited to an organic solvent.

However, at this time, the spray unit 230 has the temperature of the dry charcoal DC introduced into the main bodies 210 and 310 (for example, about 80 ° C. to 150 ° C.) and the desired drying when discharged from the main bodies 210 and 310. The difference from the temperature of the charcoal DC (for example, about 50 ° C.) is sprayed with the minimum amount of water that can be endothermic by latent heat and sensible heat. This makes it possible to cool the dry coal DC while avoiding the situation where liquid water adheres to the dry coal DC (while maintaining the dry state of the dry coal DC).

Further, even if the spray unit 230 sprays a slightly larger amount of water than the minimum amount capable of absorbing the above difference by latent heat and sensible heat, the adhesion of liquid water is suppressed and the dry charcoal DC is cooled. be able to.

Specifically, hydrous coal (before drying) such as lignite BC contains free water and combined water in the first place. Free water is water that exists in the macroscopic voids inside the hydrous coal on the surface of the hydrous coal, and exhibits the same thermophysical characteristics as bulk water. The bound water is water condensed in the capillary tube of the hydrous coal, adsorbed water having multiple layers or a single layer on the surface of the hydrous coal, and bound water bonded to hydrogen on the surface of the hydrous coal. Since bound water is harder to evaporate than free water, it requires more thermal energy than free water to evaporate bound water.

FIG. 4 is a diagram illustrating free water and combined water. In FIG. 4, the ratio of water contained in lignite (moisture content of lignite) is shown on the horizontal axis, and the temperature (° C.) of water vapor in contact with lignite is shown on the vertical axis. As shown in FIG. 4, when steam at 100 ° C. is brought into contact with lignite and heated at normal pressure, the water content of lignite decreases to about 30%. As described above, among the water contained in lignite, the water that vaporizes at about 100 ° C. is free water. On the other hand, when steam exceeding 100 ° C. and lower than 200 ° C. is brought into contact with lignite and heated, the water content of lignite decreases to about 3%. As described above, among the water contained in lignite, the water that vaporizes above 100 ° C. and below 200 ° C. is the bound water. That is, free water requires less heat energy (heat of vaporization, heat of vaporization) for vaporization than bound water.

Here, the liquid water that adheres to the dry coal DC when the spray unit 230 sprays water only stays on the surface of the dry coal DC. That is, the liquid water adhering to the dry coal DC becomes free water. Therefore, even if the spray unit 230 sprays a larger amount of water than the amount capable of absorbing the above difference by latent heat and sensible heat, it will be vaporized while being stored in the storage unit 130.

Therefore, the spray unit 230 sprays the amount of water that vaporizes while being stored in the storage unit 130 to the minimum amount that can absorb the above difference by latent heat and sensible heat, thereby causing the liquid water to adhere. It is possible to prevent and cool the dry coal DC. Further, by spraying water as a liquid, the dry coal DC can be cooled at a lower cost as compared with the configuration of spraying an organic solvent.

Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to such embodiments. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the claims, and it is understood that they also naturally belong to the technical scope.

For example, in the first embodiment, the water cooling device has been described as an example as the first cooling unit 220. However, the configuration of the first cooling unit 220 is not limited as long as the main body 210 can be cooled. For example, the first cooling unit 220 may be composed of an air cooling device or a Pelche element. Further, the first cooling unit 220 is not an indispensable configuration.

Further, in the first embodiment, the device for circulating the refrigerant as the second cooling unit 244 has been described as an example. However, the configuration of the second cooling unit 244 is not limited as long as the gas can be cooled and condensed. For example, the second cooling unit 244 may be composed of a Perche element.

Further, in the first and second embodiments, methanol is taken as an example as an example of the organic solvent (liquid) sprayed by the spray unit 230. However, the organic solvent may have a boiling point of 100 ° C. or lower. For example, as an organic solvent, alcohols such as methanol, ethanol, propanol and butanol, hydrocarbons such as pentane, hexane, heptane and benzene, esters such as methyl acetate, ethyl acetate and propyl acetate, ketones such as acetone and methyl ethyl ketone, diethyl ether , Ethyl such as tetrahydrofuran, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, halides such as dichloroethylene and trichlorethylene, petroleum products such as gasoline and kerosene, and mixtures thereof.

Further, in the first and second embodiments, the configuration in which the cooling devices 120 and 320 include the condensing unit 240 has been described as an example. However, the condensing unit 240 is not an essential configuration.

Further, as the hydrous coal, lignite was taken as an example for explanation. However, the hydrous coal may be peat, lignite, or subbituminous coal, or may be a mixture of any two or more of peat, lignite, lignite, and subbituminous coal.

The present disclosure can be used in a cooling device for cooling hydrous coal dried by heating.

120 Cooling device 230 Spraying part 240 Condensing part 320 Cooling device

Claims (2)

An introduction port into which the hydrous coal dried by heating is introduced, a main body portion provided below the introduction port and a discharge port from which the hydrous coal is discharged are formed, and a main body portion.
A disperser provided in the main body to disperse the introduced hydrous coal, and
Below the disperser in the main body, a spray unit that sprays an organic solvent having a boiling point of 100 ° C. or lower, and a spray unit.
Cooling device equipped with. The organic solvent sprayed by the spray unit is provided with a condensing unit that cools and condenses the vaporized gas by contacting with the dried hydrous coal.
The cooling device according to claim 1, wherein the spray unit sprays the organic solvent produced in the condensing unit onto the dried hydrous coal.

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