JP6686356B2 - Drying system and method of starting the drying system - Google Patents

Description

  The present invention relates to a drying system for drying brown coal using steam and a method for starting the drying system.

  Coal has a useful life of about 150 years, which is more than three times that of petroleum, and because reserves are not unevenly distributed compared to petroleum, it is a natural resource that can be stably supplied for a long time. Is expected as. Coal is classified into peat, lignite, lignite, subbituminous coal, bituminous coal, semi-anthracite and anthracite in order of low carbon content. Compared with anthracite and anthracite (hereinafter referred to as anthracite, etc.), the water content (water content) is high.

  Among the hydrous coal, lignite is said to occupy half of the world's coal reserves, so effective utilization of lignite is being studied. However, as described above, water-containing coal such as brown coal has a higher water content than that of anthracite, so that the calorific value per unit weight is low and the energy efficiency as a fuel for transportation costs is low.

  Therefore, by supplying high-temperature fluidized gas from the bottom of the storage tank containing the hydrous coal, a fluidized bed of the hydrous coal is formed in the storage tank, and the heat of the fluidized gas is added to the hydrous coal to produce the hydrous coal. A technique for drying the oil has been developed (for example, Patent Document 1).

Japanese Patent Laid-Open No. 5-117661

Since brown coal contains a large amount of volatile organic substances, if a gas containing oxygen (O ₂ ) (for example, air) is used as a fluidizing gas when drying the brown coal, the brown coal may be burned by oxygen. There is. For this reason, it is necessary to use a gas that does not contain oxygen as the fluidizing gas, but there is a problem that, for example, nitrogen is costly.

  Therefore, it is conceivable to use steam as the fluidizing gas. However, when steam is used, the particles of brown coal agglomerate when starting the drying of the brown coal, the fluidity of the particles of the brown coal is impaired, and efficient drying may not be possible.

  Then, in view of such a subject, this invention aims at providing the drying system which can suppress the aggregation of brown coal, and can dry brown coal efficiently, and the starting method of a drying system.

In order to solve the above-mentioned problem, the drying system of the present invention provides a container for accommodating an object to be contained containing at least lignite and steam from the bottom surface of the container to store the object in the container. Along with forming a fluidized bed by fluidizing, a steam supply unit for drying the brown coal by the steam, and an introduction unit for introducing at least the brown coal into the storage unit, and when starting the drying of the brown coal, The water vapor supply unit supplies water vapor to the accommodation unit to form a fluidized bed of heat storage particles, which has a mass density higher than that of the brown coal and does not react at the temperature of the water vapor, in the accommodation unit, When the temperature of the heat storage particles becomes equal to or higher than a predetermined temperature, the introduction unit introduces the brown coal into the storage unit, and the steam supply unit causes the heat storage particles and the heat storage particles in the storage unit. Wherein as fluidized bed lignite are mixed is formed, by adjusting the flow rate of the steam supplied to the accommodation portion, when turned temperature than the temperature of the brown coal is predetermined, the steam supply unit, the housing The flow rate of the steam supplied to the accommodating part is adjusted so that a fixed bed of the heat storage particles and a fluidized bed of the brown coal are formed in the part.

  The water vapor supply unit supplies water vapor at a first flow rate capable of causing the heat storage particles to flow to form a fluidized bed of the heat storage particles in the accommodation unit, and the water vapor supply unit is less than the first flow rate and is less than the first flow rate. Water vapor is supplied at a second flow rate that is equal to or higher than the minimum fluidization speed of the heat storage particles to form a fluidized bed of the heat storage particles and the brown coal in the accommodation unit, and the temperature of the brown coal becomes equal to or higher than a predetermined temperature. Then, steam is supplied at a third flow rate that is less than the minimum fluidization rate of the heat storage particles and is equal to or higher than the minimum fluidization rate of the brown coal, and the fixed bed of the heat storage particles and the fluidized bed of the brown coal are stored in the accommodation unit. May be formed.

  Moreover, when the temperature of the brown coal becomes equal to or higher than a predetermined temperature, an extraction unit may be provided that extracts the heat storage particles from the storage unit.

  Further, the heat storage particles may be alumina.

In order to solve the above-mentioned problems, a method for starting a drying system according to the present invention comprises supplying water vapor from the bottom surface of a storage unit to cause a contained object containing at least lignite to flow in the storage unit to form a fluidized bed. A method of starting a drying system for drying the brown coal with the steam, wherein steam is supplied to the storage unit, the mass density of the steam in the storage unit is larger than that of the brown coal, and the target does not react at the temperature of the steam. A fluidized bed of heat storage particles that are contained is formed, and when the temperature of the heat storage particles becomes equal to or higher than a predetermined temperature, the brown coal is introduced into the storage unit, and the flow rate of steam supplied to the storage unit is adjusted. to, the heat storage particles and the brown coal forms a fluidized bed mixed within the accommodation portion, when turned temperature than the temperature of the brown coal is predetermined, water supplied to the receiving portion Adjust the flow rate of the gas, and forming a fluidized bed of the brown coal and the fixed layer of the heat storage particles within the housing portion.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress the aggregation of brown coal and to dry brown coal efficiently.

It is a figure for demonstrating a drying system. It is a figure for explaining control by a control part at the time of starting a drying system. It is a figure for demonstrating the flow of a process of the starting method of a drying system.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the invention unless otherwise specified. In this specification and the drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to omit redundant description, and elements not directly related to the present invention are omitted. To do.

  FIG. 1 is a diagram for explaining the drying system 100. In FIG. 1, the flow of brown coal is shown by a solid arrow, the flow of water vapor is shown by an outline arrow, the flow of a heat medium is shown by an alternate long and short dash line, and the flow of control commands is shown by a dashed arrow. As shown in FIG. 1, the drying system 100 includes an introduction unit 110, a storage unit 120, a steam supply unit 130, a heat transfer tube 140, a control unit 150, and a separation device 160.

  The introduction unit 110 introduces the brown coal into the accommodation unit 120 under the control of the control unit 150 described below. In addition, during normal operation, the introduction unit 110 continuously introduces the brown coal into the accommodation unit 120 at a predetermined rate (kg / h).

  The accommodation part 120 is provided with an introduction port 122a, and the brown coal is introduced from the introduction part 110 through the introduction port 122a. And the accommodation part 120 accommodates the brown coal (object to be accommodated) introduced by the introduction part 110. Further, the bottom surface of the housing portion 120 is provided with a withdrawal portion 124 including an extraction pipe 124a and a valve 124b provided in the extraction pipe 124a. The valve 124b is closed during normal operation and is controlled to be opened and closed by the control unit 150.

  The water vapor supply unit 130 includes a wind box 132 and a water vapor delivery unit 134 that sends water vapor to the air box 132. The wind box 132 is provided below the housing section 120, and when the drying system 100 is operated, water vapor is supplied from the bottom surface of the housing section 120 into the housing section 120 through the wind box 132.

  More specifically, the upper part of the wind box 132 also functions as a bottom surface of the housing portion 120 and is formed of a ventilation plate 132a that is breathable. The dispersion plate 132a may be, for example, a plate provided with a plurality of apertures having a diameter smaller than the particle size of an object to be contained (brown coal and heat storage particles described later), or an aperture having a diameter smaller than the particle size of the object to be contained. It is composed of a plate on which the provided nozzle is installed. The water vapor delivery unit 134 supplies water vapor into the housing unit 120 through the openings of the dispersion plate 132a. The water vapor thus supplied to the housing part 120 causes the contained object to flow in the accommodating part 120 to form a fluidized bed, and the high temperature (100 ° C. or more, for example, 110 ° C.) steam is brought into contact with the contained object. To dry the brown coal.

  In addition, a heat transfer tube 140 is provided in the housing portion 120, and a heat medium (for example, steam) is supplied to the heat transfer tube 140 from a supply source (not shown). With the configuration including the heat transfer tube 140, heat is exchanged between the heat medium and the steam in the accommodation section 120, and the steam moving upward can be further heated. As a result, the drying of brown coal by steam is further promoted.

  The control unit 150 is composed of a semiconductor integrated circuit including a CPU (central processing unit), reads a program and parameters for operating the CPU itself from the ROM, and cooperates with the RAM as a work area and other electronic circuits. Manage and control the entire drying system 100. In the present embodiment, the control unit 150 controls the introduction unit 110, the steam supply unit 130 (steam delivery unit 134), and the extraction unit 124 (valve 124b). Control of the introduction unit 110, the steam supply unit 130, and the extraction unit 124 by the control unit 150 will be described in detail later.

  In addition, the separation unit 160 is connected to the housing portion 120 via a gas discharge port 122b provided in the upper portion and a gas discharge pipe 122c connected to the gas discharge port 122b. The accommodating part 120 sends out the particulate lignite scattered in the accommodating part 120 to the separation device 160 together with the gas in the accommodating part 120 (the steam supplied from the steam supply part 130 and the steam evaporated from the lignite). . The separator 160 is a solid-gas separator (cyclone), separates gas (steam) from solid (particulate brown coal), and the separated particulate brown coal is discharged from the downcomer 162.

  Further, the accommodation section 120 is provided with a discharge port 122d, and when undried brown coal is introduced from the introduction port 122a, the volume of the fluidized bed is increased thereby, and the dried brown coal overflows from the discharge port 122d. Then, the dried lignite can be obtained by discharging the lignite to the outside of the housing section 120.

  As described above, in the drying system 100, the brown coal is dried by the steam. However, when the drying of the brown coal is started (when the drying system 100 is started), the brown coal is aggregated and the fluidity is increased. May be damaged. Specifically, among brown coal, brown coal having a predetermined particle size (hereinafter, referred to as “aggregated particle size”) or less may be aggregated by water (liquid), and aggregated in a lump (so-called agglomerate). ). Since the agglomerates have extremely low fluidity, if the agglomerates are generated in the storage section 120, it becomes difficult to form a fluidized bed, and brown coal cannot be dried.

  Further, before the drying system 100 is activated, the inside of the storage unit 120 is empty (no solid matter such as brown coal is stored in the storage unit 120), and the ambient temperature in the storage unit 120 is room temperature (for example, 5 ℃ ~ 35 ℃). When the drying system 100 is activated, the steam supply unit 130 supplies high-temperature steam into the housing unit 120, and the introduction unit 110 introduces brown coal at room temperature into the housing unit 120. Then, the solid matter accommodated in the accommodating portion 120 is only the lignite at room temperature, and when the lignite at room temperature comes into contact with the water vapor, the water vapor is condensed and becomes water (liquid). Then, brown coal having an aggregate particle size or less aggregates to form a lump-shaped aggregate, and a fluidized bed is not formed.

  Therefore, in the present embodiment, in the drying system 100, before the brown coal that is the main contained object is dried, other particles are introduced into the accommodating portion 120 as the contained object to preheat the inside of the accommodating portion 120.

  FIG. 2 is a diagram for explaining control by the control unit 150 when starting the drying system 100. In addition, in order to facilitate understanding, in FIG. 2, the extraction unit 124, the heat transfer tube 140, and the separation device 160 are omitted. In FIG. 2, the heat storage particles are shown by white circles and the brown coal is shown by black circles.

  As shown in FIG. 2 (a), before starting the drying of the brown coal, the control unit 150 controls the introduction unit 110 to introduce the heat storage particles (objects to be contained) into the accommodation unit 120 and supply steam. The part 130 (steam delivery part 134) is controlled to supply high-temperature (100 ° C. or higher, for example, 110 ° C.) steam to the housing part 120. Here, the heat storage particles are solid particles having a larger mass density than brown coal and not reacting at the temperature of water vapor, and are, for example, alumina.

  At this time, the control unit 150 controls the water vapor supply unit 130 to supply the water vapor at a first flow rate that allows the heat storage particles to flow, and forms a fluidized bed of the heat storage particles in the accommodation unit 120. Here, the first flow velocity is an arbitrary flow velocity equal to or higher than the minimum fluidization velocity Umf of the heat storage particles (for example, 3 Umf_heat storage particles).

  Then, the high temperature water vapor forms a fluidized bed of the heat storage particles in the housing portion 120 and heats the heat storage particles. In addition, in the present embodiment, since the introduction unit 110 introduces the heat storage particles in the storage unit 120 in an amount that does not overflow from the discharge port 122d, the heat storage particles are not discharged from the discharge port 122d.

  Then, when the temperature of the heat storage particles measured by the temperature measuring unit (not shown) reaches a predetermined drying temperature, the control unit 150 controls the introducing unit 110 as illustrated in FIG. 2B. Then, the brown coal is introduced into the accommodating portion 120. Here, the drying temperature is a temperature higher than the saturation temperature of water vapor (for example, 110 ° C.). By setting the heat storage particles to the drying temperature, condensed water (liquid) generated by contact of steam with normal temperature brown coal is evaporated, and as a result, brown coal aggregation can be prevented.

  Further, the control unit 150 controls the steam supply unit 130 to adjust the flow rate of the steam supplied to the housing unit 120 so that the fluidized bed of the heat storage particles and the brown coal is formed in the housing unit 120. More specifically, the control unit 150 controls the steam supply unit 130 to supply steam at a second flow rate that is lower than the first flow rate and is equal to or higher than the minimum fluidization rate of the heat storage particles. When the second flow velocity is equal to or higher than the minimum fluidization speed of the heat storage particles, a fluidized bed in which brown coal and heat storage particles are mixed can be formed. Further, when the second flow velocity is lower than the first flow velocity, it becomes possible to suppress the scattering of lignite from the surface of the fluidized bed.

  Then, when the temperature of the brown coal reaches the drying temperature, as shown in FIG. 2C, the control unit 150 controls the steam supply unit 130 so that the fixed layer of the heat storage particles and the brown coal are stored in the storage unit 120. The flow rate of the steam supplied to the containing portion 120 is adjusted so that a fluidized bed is formed. Specifically, the control unit 150 controls the steam supply unit 130 to supply steam at a third flow rate that is lower than the minimum fluidization rate of the heat storage particles and equal to or higher than the minimum fluidization rate of the brown coal. Since the third flow velocity is lower than the minimum fluidization speed of the heat storage particles, the fixed layer of the heat storage particles can be formed in the lower portion of the accommodation section 120. Further, since the third flow velocity is equal to or higher than the minimum fluidization rate of brown coal, it becomes possible to form a fluidized bed of brown coal on the fixed bed of the heat storage particles.

  Then, the control unit 150 opens the valve 124b (see FIG. 1) and extracts the heat storage particles that are the fixed layer from the housing unit 120.

  In this way, the start-up of the drying system 100 is completed and the normal operation is started. Then, by introducing the undried brown coal, the volume of the fluidized bed formed by the brown coal is increased, and the heated and dried brown coal overflows from the discharge port 122d and is discharged to the outside of the housing section 120.

  As described above, in the present embodiment, before the brown coal is dried with steam, the heat storage particles are introduced into the housing section 120 to be fluidized and heated. Since the heat storage particles do not aggregate with water vapor, a fluidized bed of lignite at a drying temperature can be formed in the housing portion 120. Then, even if the brown coal is introduced into the storage unit 120 that stores the heat storage particles (solid matter) heated to the drying temperature and the steam is supplied, the heat of the heat storage particles and the heat of the steam are transferred to the brown coal. Therefore, even if water vapor contacts the brown coal, it does not condense, or the amount of condensed water can be reduced. Further, since the heat storage particles have a large mass density and a large motion inertia, they also play a role of destroying the agglomerated brown coal. This makes it possible to suppress the aggregation of the brown coal and to efficiently dry the brown coal.

  Further, when the brown coal reaches the drying temperature, the heat storage particles overflow from the discharge port 122d by the structure that adjusts the flow rate of the steam so that the fixed layer of the heat storage particles and the fluidized bed of the brown coal are formed in the accommodation section 120. Without doing so, it is possible to overflow only the brown coal and discharge it to the outside.

(Method of starting the drying system 100)
Next, a method of starting the drying system 100 will be described. FIG. 3 is a diagram for explaining the processing flow of the activation method of the drying system 100. In the method of starting the drying system 100, when the user inputs a stop instruction, the control unit 150 stops the process being executed at that time.

  As shown in FIG. 3, first, the control unit 150 controls the introduction unit 110 to introduce the heat storage particles into the storage unit 120, and controls the steam supply unit 130 to supply the storage unit 120 with steam to store the heat storage particles. A fluidized bed of heat storage particles is formed in the part 120 (S110).

  Then, the control unit 150 determines whether the temperature of the heat storage particles is equal to or higher than the drying temperature (S120), and maintains the fluidized bed of the heat storage particles until the temperature is equal to or higher than the drying temperature (NO in S120).

  When the temperature of the heat storage particles becomes equal to or higher than the drying temperature (YES in S120), the control unit 150 controls the introduction unit 110 to introduce brown coal into the storage unit 120, and controls the steam supply unit 130 to store the same in the storage unit 120. The flow rate of the supplied steam is adjusted to form a fluidized bed in which the heat storage particles and the brown coal are mixed in the accommodation section 120 (S130).

  Then, the control unit 150 determines whether or not the temperature of the brown coal is equal to or higher than the drying temperature (S140), and maintains the fluidized bed in which the heat storage particles and the brown coal are mixed until the temperature is equal to or higher than the drying temperature (NO in S140). The heat of the heat storage particles is transferred to the brown coal.

  When the temperature of the brown coal becomes equal to or higher than the drying temperature (YES in S140), the control unit 150 controls the water vapor supply unit 130 to adjust the flow rate of the water vapor supplied to the storage unit 120, and the heat storage particles of the heat storage particles are stored in the storage unit 120. A fluidized bed of fixed coal and brown coal is formed (S150).

  Then, the control unit 150 opens the valve 124b of the extraction unit 124 to extract the heat storage particles from the storage unit 120 (S160).

  As described above, according to the drying system 100 and the activation method of the drying system 100 according to the present embodiment, when the drying system 100 is activated, first, the heat storage particles are introduced to form the fluidized bed with steam. With a simple structure, it is possible to suppress the aggregation of brown coal and efficiently dry the brown coal. Thereby, the transportation cost of brown coal can be reduced and energy efficiency can be improved.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such embodiments. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the claims, and it should be understood that these also belong to the technical scope of the present invention. To be done.

  For example, in the above-described embodiment, the configuration has been described in which the drying system 100 includes the extraction unit 124 and the heat storage particles are extracted from the accommodation unit 120 when the temperature of the brown coal becomes equal to or higher than the drying temperature. However, the extraction unit 124 is not an essential component. In the configuration without the extraction unit 124, the heat storage particles remain stored in the storage unit 120, and the introduction unit 110 does not introduce the heat storage particles. In this case, the control unit 150 controls the steam supply unit 130 to form a fluidized bed of heat storage particles or a fixed layer of heat storage particles in the accommodation unit 120.

  Moreover, in the said embodiment, the case where the introduction part 110 transfers to the normal operation which introduce | transduces lignite into the accommodating part 120 continuously after the extraction part 124 extracted heat storage particles was mentioned as the example. However, the heat storage particles may be extracted after shifting to the normal operation.

  Further, although alumina has been described as an example of the heat storage particles in the above embodiment, solid particles having a mass density higher than that of brown coal and not reacting at the temperature of steam may be used. For example, the heat storage particles may be made of a metal such as silica or iron.

  INDUSTRIAL APPLICATION This invention can be utilized for the drying system which dries brown coal using steam, and the starting method of a drying system.

100 Drying system 110 Introductory part 120 Housing part 124 Extraction part 130 Steam supply part

Claims (5)

A storage unit for storing an object to be contained including at least brown coal;
Water vapor is supplied from the bottom surface of the containing portion to form a fluidized bed by flowing the contained object in the containing portion, and a steam supplying portion for drying the brown coal with the water vapor,
An introducing unit for introducing at least the brown coal into the accommodating unit;
Equipped with
When starting the drying of the brown coal,
The water vapor supply unit supplies water vapor to the accommodation unit to form a fluidized bed of heat storage particles, which is the contained material, having a mass density higher than that of the brown coal and does not react at the temperature of the water vapor in the accommodation unit. ,
When the temperature of the heat storage particles is equal to or higher than a predetermined temperature, the introducing unit introduces the brown coal into the containing unit,
The water vapor supply unit adjusts the flow rate of water vapor supplied to the accommodation unit such that a fluidized bed in which the heat storage particles and the brown coal are mixed is formed in the accommodation unit,
When the temperature of the brown coal becomes equal to or higher than a predetermined temperature, the water vapor supply unit supplies the storage unit so that a fixed layer of the heat storage particles and a fluidized bed of the brown coal are formed in the storage unit. A drying system, characterized in that the flow rate of water vapor is adjusted. The water vapor supply unit,
Water vapor is supplied at a first flow rate capable of causing the heat storage particles to flow, and a fluidized bed of the heat storage particles is formed in the accommodation portion,
Water vapor is supplied at a second flow rate that is less than the first flow rate and is equal to or higher than the minimum fluidization rate of the heat storage particles to form a fluidized bed of the heat storage particles and the brown coal in the accommodation unit,
When the temperature of the brown coal becomes equal to or higher than a predetermined temperature, steam is supplied at a third flow rate that is lower than the minimum fluidization rate of the heat storage particles and is equal to or higher than the minimum fluidization rate of the brown coal, and the inside of the accommodation unit is supplied. 2. The drying system according to claim 1, wherein a fixed bed of the heat storage particles and a fluidized bed of the brown coal are formed in.   The drying system according to claim 1 or 2, further comprising: an extraction unit that extracts the heat storage particles from the storage unit when the temperature of the brown coal becomes equal to or higher than a predetermined temperature.   The drying system according to any one of claims 1 to 3, wherein the heat storage particles are alumina. A method for starting a drying system, which comprises supplying water vapor from the bottom surface of the containing portion to form a fluidized bed by flowing an object to be contained containing at least brown coal in the containing portion and drying the brown coal with the water vapor,
Supplying water vapor to the accommodation portion, in the accommodation portion, a mass density is larger than the brown coal, to form a fluidized bed of heat storage particles that is the contained object that does not react at the temperature of the water vapor,
When the temperature of the heat storage particles is equal to or higher than a predetermined temperature, the brown coal is introduced into the storage unit,
By adjusting the flow rate of the water vapor supplied to the storage unit, a fluidized bed in which the heat storage particles and the brown coal are mixed is formed in the storage unit,
When the temperature of the brown coal becomes equal to or higher than a predetermined temperature, the flow rate of the steam supplied to the storage unit is adjusted to form a fixed bed of the heat storage particles and a fluidized bed of the brown coal in the storage unit. Characteristic drying system start-up method.

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