JP6878839B2 - 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, etc.).

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 for 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 mixes a cooled object obtained by heating and drying a hydrous coal with solid particles having a temperature lower than that of the cooled object. The mixing unit for heat exchange and the separation unit for separating the mixture of the object to be cooled and the solid particles generated by the mixing unit into the object to be cooled and the solid particles, and the separation unit. A cooling unit for cooling the separated solid particles is provided , and the mixing unit includes a cooled object obtained by heating and drying the hydrous coal, and the solid particles cooled by the cooling unit. And are mixed to exchange heat .

Further, the solid particles are larger than the object to be cooled, and the separation portion may be configured to include a phloem portion in which a hole through which only the object to be cooled passes is formed.

In addition, a control unit that controls the amount of the solid particles introduced into the mixing unit may be provided so that the object to be cooled separated by the separation unit has a temperature lower than a predetermined temperature.

Further, the solid particles may be composed of at least copper.

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.

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. To 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 accommodating tank. The heat transfer tube is arranged in the storage 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 (dry coal DC (object to be cooled)) 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 the cooling device 120. As shown in FIG. 2, the cooling device 120 includes a mixing unit 210, a mixture transfer device 212, a separation unit 220, a dry charcoal transfer device 222, a solid particle transfer device 224, a cooling unit 230, and a return device 232. , A temperature measuring unit 240, and a control unit 250. In FIG. 2, the flow of the dry coal DC, the solid particle SP, and the mixture MX is indicated by a solid arrow, and the signal flow is indicated by a broken line.

Dry charcoal DC is introduced into the mixing unit 210 from the drying device 110. Further, the solid particle SP is introduced into the mixing unit 210 by the return device 232 described later. The mixing unit 210 mixes the dry coal DC and the solid particles SP having a temperature lower than that of the dry coal DC (for example, about room temperature (25 ° C.)) for a predetermined time. Here, the predetermined time (contact time) is such that the temperatures of the dry coal DC and the solid particles SP come into contact with each other so that the temperatures of the two are substantially equal to each other. In this embodiment, the solid particle SP is composed of copper (Cu). That is, the solid particle SP is a copper particle.

The mixing unit 210 includes, for example, a housing, a shaft, rotary blades, and a motor. Dry charcoal DC and solid particle SP are introduced into the housing. The shaft is provided in the housing so that the longitudinal direction is along the horizontal direction. The rotary blade has a flat plate shape and is fixed to the shaft. The rotary blades are erected radially from the outer peripheral surface of the shaft. The motor rotates the shaft. Since various existing techniques can be applied to the technique of mixing two kinds of solids such as dry coal DC and solid particle SP, detailed description thereof will be omitted here.

Due to the configuration including the mixing unit 210, the dry coal DC (about 80 ° C. to 150 ° C.) and the low-temperature solid particle SP are in contact with each other for a predetermined time, and heat exchange is performed between the dry coal DC and the solid particle SP. It becomes. That is, heat is transferred from the dry coal DC to the solid particle SP, which cools the dry coal DC.

Since the solid particle SP is a solid, it has a higher thermal conductivity than a gas. Therefore, the dry coal DC can be cooled with an extremely small amount of solid particle SP as compared with the conventional technique of cooling with an inert gas. This makes it possible to efficiently cool the dry coal DC at low cost.

Further, as described above, the solid particle SP of the present embodiment is a copper particle. Copper has a relatively large thermal conductivity of about 400 W · m ^-1 · K ^{-1 among solids.} Therefore, by using the copper particles as the solid particles SP, the dry coal DC can be cooled more efficiently.

As described above, the mixture MX (for example, about 50 ° C.) of the dry coal DC and the solid particle SP generated by the mixing unit 210 is introduced into the separation unit 220 by the mixture transfer device 212 (for example, a conveyor). ..

The separation unit 220 separates the mixture MX produced by the mixing unit 210 into the dry coal DC and the solid particles SP.

In the present embodiment, the solid particle SP is larger than the dry coal DC. That is, the solid particle SP is larger than the maximum particle size of the dry coal DC. The separation unit 220 includes a phloem portion in which a hole through which only the dry charcoal DC passes is formed, and a vibrating portion that vibrates the phloem portion. Here, the sieve portion is, for example, a sieve having rectangular pores and a size of opening slightly larger than the maximum particle size of the dry coal DC. For example, when the maximum particle size of the dry coal DC is 3 mm, the opening of the sieve portion is about 3.1 mm. Further, in this case, the solid particle SP may have a size (for example, about 5 mm to 6 mm) that does not pass through the pores. That is, the phloem is designed so that the relationship of the maximum particle size of the dry coal DC <the size of the pores of the phloem <the particle size of the solid particles SP is established. Since various existing techniques can be applied to the technique for separating solids according to the size of particles, detailed description thereof will be omitted here.

The dry coal DC separated by the separation unit 220 is introduced into the storage unit 130 by the dry coal transfer device 222 (for example, a conveyor) and stored in the storage unit 130. On the other hand, the separated solid particle SP is introduced into the cooling unit 230 by the solid particle transport device 224 (for example, a conveyor).

The cooling unit 230 is composed of, for example, an air cooling device, and cools the solid particles SP separated by the separation unit 220. The return device 232 is composed of, for example, a conveyor, and introduces the cooled solid particle SP into the mixing unit 210 based on a control command by the control unit 250 described later.

The solid particle SP can be reused by the configuration including the cooling unit 230 and the return device 232. Therefore, it is possible to further cool the dry coal DC at low cost.

The temperature measuring unit 240 measures the temperature of the dry coal DC introduced into the mixing unit 210, that is, the temperature of the dry coal DC discharged from the drying device 110. Further, the temperature measuring unit 240 measures the temperature of the dry coal DC separated by the separating unit 220.

The control unit 250 is composed of a semiconductor integrated circuit including a CPU (Central Processing Unit). The control unit 250 reads a program, parameters, and the like for operating the CPU itself from the ROM, and manages and controls the entire cooling device 120 in cooperation with the RAM as a work area and other electronic circuits.

In the present embodiment, the control unit 250 controls the return device 232 based on the temperature of the dry coal DC measured by the temperature measurement unit 240. Specifically, the control unit 250 describes the temperature of the dry coal DC introduced into the mixing unit 210, the amount of the dry coal DC introduced into the mixing unit 210, and the residence time (contact time) of the dry coal DC in the mixing unit 210. ), Based on the temperature of the solid particles SP introduced into the mixing unit 210 (the temperature of the solid particles SP cooled by the cooling unit 230), the dry charcoal DC separated by the separating unit 220 has a predetermined temperature (). For example, the amount of the solid particle SP to be introduced into the mixing unit 210 is derived so as to be lower than the ignition temperature). Then, the control unit 250 controls the return device 232 so that the derived amount of the solid particle SP is introduced into the mixing unit 210.

With the configuration including the control unit 250, the dry coal DC separated by the separation unit 220 can be maintained at a temperature lower than the temperature desired by the user. For example, assume that the control unit 250 derives the amount of solid particle SP to be introduced into the mixing unit 210 so that the dry coal DC separated by the separation unit 220 becomes lower than the ignition temperature. In this case, it is possible to avoid a situation in which the dry coal DC separated by the separation unit 220 (the dry coal DC transported by the dry coal transfer device 222 and the dry coal DC stored in the storage unit 130) ignites. It becomes.

As described above, according to the cooling device 120 according to the present embodiment, the dry coal DC can be produced at low cost by a simple configuration in which the solid particles SP having a temperature lower than that of the dry coal DC and the dry coal DC are simply mixed. It becomes possible to cool.

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 above embodiment, the case where the solid particle SP is a copper particle has been described as an example. However, the solid particle SP may be composed of at least copper (for example, a copper alloy or the like). Further, the solid particle SP is not limited to copper, and may be composed of a metal such as aluminum (Al). Metals have a higher thermal conductivity than other solids. Therefore, by forming the solid particle SP with a solid containing a metal, the dry coal DC can be efficiently cooled. Further, the solid particle SP is not limited to a metal, and the material is not limited as long as it is a solid such as a nonflammable solid particle such as a metal oxide (ceramic) such as alumina and a flammable solid particle such as biomass. In any case, by forming the solid particle SP with a solid, the dry charcoal DC can be cooled with an extremely small amount of the solid particle SP as compared with the conventional technique of cooling with an inert gas.

Further, in the above embodiment, the case where the separation unit 220 is configured to include the phloem unit has been described as an example. Therefore, the cost of the separation unit 220 itself can be reduced. However, the structure of the separation unit 220 is not limited as long as the dry coal DC and the solid particle SP can be separated depending on the particle size. The separation unit 220 may be composed of, for example, a centrifuge or a sedimentation separator.

Further, in the above embodiment, the case where the solid particle SP is larger than the maximum particle size of the dry coal DC has been described as an example. However, the particle size of the solid particle SP may be different from that of the dry coal DC, and the solid particle SP may be smaller than the minimum particle size of the dry coal DC.

Further, as the separation unit 220, an apparatus for separating particles by mass density (for example, a centrifuge, a sedimentation separator, etc.) may be adopted. In this case, the solid particle SP is composed of a substance having a mass density different from that of the dry coal DC.

Further, in the above embodiment, the air cooling device has been described as an example of the cooling unit 230. However, the structure of the cooling unit 230 is not limited as long as the solid particle SP can be cooled. For example, the cooling unit 230 may be composed of a water cooling device, a device for cooling with another refrigerant, or a Peltier element.

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 210 Mixing unit 220 Separation unit 230 Cooling unit 250 Control unit

Claims (4)

A mixing part in which a material to be cooled obtained by heating and drying the hydrous coal and solid particles having a temperature lower than that of the material to be cooled are mixed and heat exchanged.
A separation unit that separates the mixture of the object to be cooled and the solid particles generated by the mixing unit into the object to be cooled and the solid particles.
A cooling unit that cools the solid particles separated by the separation unit,
Equipped with a,
The mixing unit is a cooling device that mixes and exchanges heat between the object to be cooled obtained by heating and drying the hydrous coal and the solid particles cooled by the cooling unit. The solid particles are larger than the object to be cooled and are larger.
The cooling device according to claim 1, wherein the separation unit includes a phloem unit in which a hole through which only the object to be cooled passes is formed. The invention according to claim 1 or 2 , further comprising a control unit that controls the amount of the solid particles introduced into the mixing unit so that the object to be cooled separated by the separation unit has a temperature lower than a predetermined temperature. Cooling device. The cooling device according to any one of claims 1 to 3 , wherein the solid particles contain at least copper.

Images