JP2011214806A - Fluidized bed drying equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide fluidized bed drying equipment capable of efficiently cooling a dried substance.SOLUTION: This fluidized bed drying system for fluidizing and drying brown coal 101 as the dried substance supplied to a fluidized bed drier 102 by supplying fluidizing steam 107 as a fluidizing gas to the fluidized bed drier 102, includes one or both of detecting means of a temperature meter 141 for detecting an internal temperature and a gas concentration meter 142 for detecting a concentration of an internal gas, disposed on a cooler 110 for cooling the dried brown coal (high temperature: 110°C) after drying, by cooling air 131, and a control means which detects defective cooling of the dried substance when the temperature information or the gas concentration information input by the detecting means is higher than a set value, and performs the control of adding an oxidation suppressing gas 132 to the cooling air 131 as a countermeasure to improve defective cooling.

Description

  TECHNICAL FIELD The present invention relates to a fluidized bed drying apparatus for drying a material to be dried by fluidizing gas, and in particular, fluidized bed drying capable of efficiently cooling a high temperature material to be dried discharged from the fluidized bed drying device. Regarding equipment.

  For example, a combined coal gasification power generation facility is a power generation facility that aims at further higher efficiency and higher environmental performance than conventional coal-fired power by gasifying coal and combining it with combined cycle power generation. This coal gasification combined cycle power generation facility has a great merit that it can use coal with abundant resources, and it is known that the merit can be further increased by expanding the applicable coal types. However, low-grade coal such as lignite and sub-bituminous coal has a large amount of moisture that is brought in, and there is a problem that power generation efficiency decreases due to this moisture. For this reason, it is necessary to dry the low-grade coal to remove moisture.

  Conventionally, such a fluidized bed drying apparatus for drying coal includes a drying chamber which is a dispersible plate having a plurality of openings at the bottom and a chamber chamber located at the lower portion of the drying chamber. That is, in this fluidized bed drying apparatus, fluidized gas (drying gas) is supplied from a wind box to a drying chamber through a perforated plate to dry the material to be dried while flowing (Patent Document 1 or 2). ).

  By the way, low-grade coal such as lignite and sub-bituminous coal, which is to be dried, has a low moisture value due to its high water content, so it is dried and then cooled to low temperatures for storage, transportation and use. Has been done. The low-grade coal heated to 100 ° C. or higher by the drying treatment in the fluidized bed dryer is cooled to about 50 ° C. or lower by a cooler.

  Here, in general, a fluidized bed is often used as the cooler, but the working fluid and the operating temperature differ depending on the system of the drying plant.

  Conventionally, for example, a method of cooling coal that has been treated at a high temperature of 300 ° C. to about 50 ° C. is proposed. However, the cooling of the first cooling means uses combustion exhaust gas sprayed with water as a cooling gas. However, water is not completely evaporated but is contained in the combustion exhaust gas as water droplets, and latent heat is evaporated in the cooling process to improve cooling efficiency. On the other hand, the second cooling means uses room temperature air as a cooling gas (Patent Document 3).

Japanese Patent Laid-Open No. 04-13086 Japanese Patent Laid-Open No. 06-299176 JP-A-62-115090

By the way, in the prior art, air is used as a cooling gas in a cooling process at 150 ° C. or lower. However, if uniform cooling is not performed due to imbalance of supply air or the like, the coal is partially oxidized and heated. However, there is a problem that serious troubles such as spontaneous ignition occur.
When combustion exhaust gas having a low oxygen concentration is used as cooling air, there is a problem that a large amount of exhaust gas is required and the equipment cost is increased.

  Therefore, there is an urgent need to take measures that can efficiently cool the high-temperature object to be dried discharged from the fluidized bed drying apparatus without taking such measures.

  This invention makes it a subject to provide the fluidized bed drying equipment which can cool efficiently the high temperature to-be-dried material discharged | emitted from the fluidized bed drying apparatus in view of the said problem.

  A first invention of the present invention for solving the above-described problem is a fluidized bed in which a material to be dried supplied to the fluidized bed drying apparatus is fluidized and dried by supplying a fluidized gas to the fluidized bed drying apparatus. In a drying facility, provided with a cooling means for cooling the dried object to be dried with cooling air, either a thermometer for detecting an internal temperature or a gas concentration meter for detecting an internal gas concentration, or both detection means; When the temperature information or the gas concentration information input by the detection means is larger than a set value, the cooling failure of the object to be dried is detected, and control for adding an oxidation suppression gas to the cooling air as a countermeasure for cooling failure improvement is performed. A fluidized bed drying facility comprising: a control means for performing.

  According to a second aspect of the present invention, there is provided a fluidized bed drying facility in which a material to be dried supplied to the fluidized bed drying device is fluidized and dried by supplying a fluidized gas to the fluidized bed drying device. The cooling means is divided into a plurality of cooling means according to the temperature of the high temperature cooling means for cooling the high temperature to-be-dried material discharged from the fluidized bed drying apparatus, and the cooling means to cool the to-be-dried object after cooling with cooling air One of or both of a thermometer for detecting the internal temperature and a gas concentration meter for detecting the internal gas concentration, or both of the temperature information or the gas concentration information input by the detection means are lower than a set value. A fluidized bed drying facility comprising: a control means for detecting a cooling failure of the object to be dried and controlling the addition of an oxidation-suppressing gas to the cooling air as a countermeasure for cooling failure. .

  According to a third invention, in the first or second invention, if the cooling failure is not improved even by controlling the addition of the oxidation-suppressing gas, the control means discharges a coolant or reduces the low-temperature exposure as a countermeasure for cooling failure improvement. It exists in the fluidized-bed drying equipment characterized by performing any control of supply of a dried material.

  According to a fourth invention, in the first or second invention, either or both of a thermometer for detecting the internal temperature of the line and a gas concentration meter for detecting the gas concentration in the line of the exhaust gas line discharged from the cooling means. It is in the fluidized-bed drying equipment characterized by having the detection means.

  ADVANTAGE OF THE INVENTION According to this invention, the high temperature to-be-dried material discharged | emitted from the fluidized bed drying apparatus can be cooled efficiently.

FIG. 1 is a schematic diagram showing an example of fluidized bed drying equipment to which a fluidized bed drying apparatus according to an embodiment of the present invention is applied. FIG. 2 is a schematic diagram showing an example of a combined coal gasification combined power generation system to which the fluidized bed drying facility shown in FIG. 1 is applied. FIG. 3 is a schematic view showing a fluidized bed drying facility of the first form. FIG. 4 is an operation flowchart of cooling according to the first embodiment. FIG. 5 is a schematic view showing a fluidized bed drying apparatus according to the second embodiment. FIG. 6 is a diagram showing the temperature rise characteristics of lignite.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  The present embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of fluidized bed drying equipment to which the fluidized bed drying apparatus according to the present embodiment is applied.

As shown in FIG. 1, a fluidized bed drying apparatus 100 according to the present embodiment is supplied from a supply hopper 120 and forms a drying chamber for drying lignite 101, which is a material to be dried, having a high moisture content. And a heat transfer member (heating means) 103 for supplying superheated steam (for example, 150 ° C. steam) A to the inside of the tube to remove moisture in the lignite 101, and the above described heat transfer. A generated steam line L ₁ that discharges the generated steam 104 generated when the lignite 101 is dried by the heat member 103 to the outside of the fluidized bed drying apparatus 102, and the generated steam line L ₁ are interposed in the generated steam 104. a dust collector 105 for removing dust, is interposed on the downstream side of the dust collecting apparatus 105 in generating steam line L _1, the heat recovery system 106 for recovering the steam generated 104 heat, the condenser ChiriSo 105 branches a part of the steam generated 104 dust is removed from a branch line L ₂ to be supplied to the fluidized bed dryer 102 as a fluidizing steam 107, drying brown coal withdrawn from the fluidized bed dryer 102 And a cooler 110 that cools 108 to produce product charcoal 109.
Reference numeral 116 denotes a rectifying plate that rectifies the fluidized steam 107 that is a fluidized gas.

In the fluidized bed drying facility 100, the lignite 101 is introduced into the fluidized bed drying apparatus 102 by the supply hopper 120 via the supply line L ₀ and is fluidized by the fluidized steam 107 separately introduced into the fluidized bed drying apparatus 102. Thus, the fluidized bed 111 is formed.

  The heat transfer member 103 described above is disposed in the fluidized bed 111. In the heat transfer member 103, 150 ° C. superheated steam A is supplied, and the lignite 101 is dried indirectly using the latent heat of the high temperature superheated steam A. The superheated steam A used for drying is discharged to the outside of the fluidized bed drying apparatus 102 as, for example, 150 ° C. condensed water B.

  That is, on the inner surface of the heat transfer member 103 that is a heating means, the superheated steam A condenses into a liquid (moisture), so the condensed latent heat dissipated at this time is effectively used for heating the drying of the lignite 101. . Any heating medium other than the high-temperature superheated steam A may be used as long as it is accompanied by a phase change. Examples thereof include Freon, pentane, and ammonia. In addition to using a heat medium as the heat transfer member 103, an electric heater may be installed.

Generating steam 104 generated when the brown coal 101 is dried by the heat transfer member 103 is fluidized in the fluidized bed dryer 102, by generating from the freeboard section F steam line L ₁ formed in the upper space of the fluidized bed 111 It is discharged outside the layer drying apparatus 102. Since the generated steam 104 includes a material obtained by drying and pulverizing the lignite 101, the steam 104 is collected by a dust collector 105 such as a cyclone or an electric dust collector and separated as a solid component 115.
This solid component 115 is mixed with the dry lignite 108 in the product line L ₄ extracted from the fluidized bed drying apparatus 102 via the separation line L ₃ , cooled by the cooler 110, and used as product charcoal 109. This product charcoal 109 is used as a raw material for boilers, gasifiers, and the like.

  On the other hand, since the generated steam 104 after being collected by the dust collector 105 is, for example, steam at 105 to 110 ° C., it is recovered by the heat recovery system 106, processed by the water treatment unit 112, and drained 113. As shown in FIG. Note that the generated steam 104 after being collected by the dust collector 105 may be applied to, for example, a heat exchanger, a steam turbine, or the like to effectively use the heat.

Part of the steam generated 104 after being dust collecting by a dust collector 105, is sent to the fluidized bed dryer 102 by the circulation fan 114 interposed in the branch line L _2, the fluidized bed of lignite 101 It is used as fluidized steam 107 that causes 111 to flow. As a fluidizing medium for fluidizing the fluidized bed 111, a part of the generated steam 104 is reused. However, the fluidizing medium is not limited to this. For example, nitrogen, carbon dioxide, or a low oxygen concentration containing these gases is used. Air may be used.

The fluidized bed drying apparatus 102 described above exemplifies a tube-shaped heat transfer member as the heat transfer member 103, but the present invention is not limited to this, for example, a plate-shaped heat transfer member May be used.
Moreover, although the structure which supplies superheated steam A to the heat-transfer member 103 and dries the lignite 101 indirectly was demonstrated, not only this but the lignite 101 is made into fluidized steam 107 which makes the fluidized bed 111 of the lignite 101 flow. It is good also as a structure dried directly by supplying the fluidizing gas for heating further, and drying.

  In addition, although the brown coal 101 was illustrated as to-be-dried material, as long as it has a high water content, it is good also considering to-be-dried materials, such as low grade coal containing subbituminous coal, sludge, etc., and sludge.

  An example applied to an integrated coal gasification combined cycle (IGCC) system using product coal 109 dried by the fluidized bed drying apparatus 102 shown in FIG. 1 will be described. FIG. 2 is a schematic diagram showing an example of a combined coal gasification combined power generation system to which the fluidized bed drying facility 100A shown in FIG. 1 is applied.

  As shown in FIG. 2, the coal gasification combined power generation system 200 treats pulverized coal 201 a pulverized by a mill 210 with product coal (dry lignite) 109 as a fuel and converts it into gasification gas 202. Generated by a furnace 203, a gas turbine (GT) 204 that is operated using the gasified gas 202 as fuel, and a heat recovery steam generator (HRSG) 206 that introduces turbine exhaust gas 205 from the gas turbine 204 The steam turbine (ST) 208 operated by the steam 207 and the generator (G) 209 connected to the gas turbine 204 and / or the steam turbine 208 are provided.

The coal gasification combined power generation system 200 gasifies pulverized coal 201a pulverized by a mill 210 in a coal gasification furnace 203 to obtain a gasified gas 202 which is a generated gas. The gasified gas 202 is dust-removed and gas-purified by a cyclone 211 and a gas purifier 212, and then supplied to a combustor 213 of a gas turbine 204, which is a power generation means. Is generated. The gas turbine 204 is driven by the combustion gas 214. The gas turbine 204 is connected to a generator 209, and the generator 209 generates electric power when the gas turbine 204 is driven. Since the turbine exhaust gas 205 after driving the gas turbine 204 still has a temperature of about 500 to 600 ° C., it is sent to an exhaust heat recovery boiler (HRSG) 206, where thermal energy is recovered. In the exhaust heat recovery boiler (HRSG) 206, steam 207 is generated by the thermal energy of the turbine exhaust gas 205, and the steam turbine 208 is driven by the steam 207. The exhaust gas 215 from which heat energy has been recovered by the exhaust heat recovery boiler (HRSG) 206 is released into the atmosphere via the chimney 217 after the NOx and SOx components in the exhaust gas 215 are removed by the gas purification device 216. . In the figure, reference numeral 218 denotes a condenser, 219 denotes air, 220 denotes a compressor, and 221 denotes an air separation device (ASU) that separates air into nitrogen (N ₂ ) and oxygen (O ₂ ). .

  According to this coal gasification combined cycle power generation system 200, even when gasifying using lignite 101 having a high moisture content, since the lignite 101 is dried by the efficient fluidized bed drying apparatus 102, the gasification efficiency is high. The power generation can be improved stably over a long period of time.

Moreover, in the coal gasification combined cycle power generation system 200, the efficiency of the coal-fired power plant, which has been about 40% in the past, can be improved to about 46% by combining the gas turbine and the steam turbine. By improving the plant efficiency, CO ₂ emissions can be reduced by about 13% compared to conventional coal fired boilers.

  In addition, as a power generation system using the product charcoal 109 dried with the fluidized-bed drying equipment 100 concerning this Embodiment, it is not restricted to the coal gasification combined cycle power generation system 200 mentioned above. For example, although not explicitly shown in the figure, a brown coal cooking boiler that supplies product charcoal 109 dried in the fluidized bed drying facility 100 to a boiler furnace, drives a steam turbine with steam generated in the boiler furnace, and obtains output by a generator. May be a power generation system.

[First Embodiment]
Hereinafter, the fluidized-bed drying equipment of the 1st form of this invention is demonstrated with reference to FIG.
In this embodiment, lignite cooling at 150 ° C. or lower will be described as an example, but the present invention can be applied regardless of the type of processing object and the temperature level.
As shown in FIG. 3, the fluidized bed drying apparatus 100 </ b> A according to the present embodiment supplies the fluidized vapor 107 that is a fluidized gas to the fluidized bed drying apparatus 102 to supply the fluidized bed drying apparatus 102 to be dried. In the fluidized-bed drying system for flowing and drying the lignite 101 which is a product, the temperature at which the dried lignite (high temperature: 110 ° C.) 108H after the drying is provided in the cooler 110 that cools by cooling air 131 and the internal temperature is detected. When the temperature information or the gas concentration information input by either one or both of the meter 141 or the gas concentration meter 142 for detecting the internal gas concentration and the detection device is larger than a set value, Control means (not shown) for detecting a cooling failure and controlling the addition of the oxidation-suppressing gas 132 to the cooling air 131 as a countermeasure for cooling failure.

As shown in FIG. 3, the cooler 110 uses a fluidized bed type that cools high-temperature dried lignite (for example, about 110 ° C.) 108H after drying, and uses cooling air 131 that is a fluidization and cooling medium. It is supplied by the cooling air supply means 134. Dust from the cooler 110 is removed by the dust collector 135 which is interposed in the exhaust gas line L _5.

In the present embodiment, the cooler 110, a thermometer 141 for measuring the temperature of the interior, in addition to the gas concentration meter 142 for measuring the gas concentration condition of the interior are provided, into the exhaust line L ₅ Also, a thermometer 141 for measuring the temperature inside the line and a gas concentration meter 142 for measuring the gas concentration are provided.

The thermometer 141 monitors the cooling state of the dry lignite inside the cooler 110. Normally, the dry lignite (110 ° C.) supplied to the cooler 110 is cooled to about 50 ° C. by cooling air. The status is monitored. Further, a thermometer 141 provided in the exhaust gas exhaust line L ₅ monitors whether or not the exhaust gas temperature is appropriate.
The gas concentration meter 142 monitors whether or not the cooling state of the dry lignite inside the cooler 110 is normal, and normally monitors a certain gas concentration state. Moreover, the gas concentration meter 142 provided in the exhaust line L ₅ of the exhaust gas, exhaust gas concentration to be discharged monitors a either constant.

Here, the gas concentration is measured when the oxidation of lignite accelerates, for example, the generation of CO ₂ or CO gas becomes more conspicuous than C + O ₂ = CO ₂ or C + (1/2) O ₂ = CO. is doing. Note that since there is variation in measuring the temperature distribution with the thermometer 141, it is preferable to monitor the internal state of the cooler 110 and the like with the gas concentration meter 142.

Here, the dry lignite discharged from the fluidized bed drying apparatus 102 is high-temperature dry lignite (for example, 110 ° C.) 108 H, and is cooled to 50 ° C. or less by a fluidized bed type cooler 110.
In this cooler 110, normal temperature air is used as a fluidized medium of the fluidized bed, and the lignite is cooled with this air.
Here, the temperature of the high-temperature dry lignite 108H discharged from the fluidized bed drying apparatus 102 varies, and there is a part of the high-temperature lignite, or the fluidization is uneven in the fluidized bed of the cooler 110. Further, if a staying region is generated, oxidation heat generation of the dry lignite 108H proceeds, and the lignite temperature rises and may cause spontaneous ignition.
Therefore, in the present embodiment, normal operation is continued by detecting changes (temperature, gas concentration) when a sign of spontaneous ignition appears and taking measures to reduce the heat generation rate (measures for cooling failure improvement). I have to.

As countermeasures for improving the cooling failure, countermeasures 1), the supply countermeasures for the oxidation-suppressing gas 132, the countermeasures 2), the countermeasures for discharging the high-temperature lignite inside, and the countermeasures 3), the countermeasures for supplying new low-temperature lignite are selected. The
1) Countermeasure 1) detects a temperature rise or gas concentration change (indication of spontaneous ignition) in the cooler 110 (exhaust line L ₅ ), injects an oxidation suppression gas 132 such as an inert gas, and cools The oxygen concentration in the air 131 is reduced and cooling is continued.
2) Measure 2) detects the temperature rise or gas concentration (indication of spontaneous ignition) in the cooler 110 (exhaust line L ₅ ) and raises all lignite in the cooler 110 or partially heated. The lignite is discharged and cooling of the new lignite continues.
3) Measure 3) detects the temperature rise or gas concentration (indication of spontaneous ignition) in the cooler 110 (exhaust line L ₅ ), supplies the cooled low-temperature lignite 108L, The temperature is lowered and cooling is continued.

  The rate of temperature increase due to spontaneous ignition is a function of the ambient oxygen concentration and the temperature of the processed material. Since the response of these factors is relatively high, injection of the oxidation-suppressing gas 132 and supply of low-temperature lignite 108L should be performed. Thus, spontaneous ignition can be prevented by reducing the temperature rise rate by reducing the oxygen concentration or by lowering the temperature of the treated product and continuing cooling.

  The control means is constituted by a microcomputer or the like. The control means is composed of a RAM, a ROM, etc., and is provided with a storage unit (not shown) in which programs and data are stored. The data stored in the storage unit detects a cooling failure (including a sign of spontaneous ignition) of the dry lignite 108H when a temperature rise or gas concentration change in the cooler 110 is confirmed. The control means is connected to the gas supply means 151, the lignite discharge means 152, and the low temperature lignite supply means 153. This control means controls the gas supply means 151, the brown coal discharge means 152, and the low temperature brown coal supply means 153 according to the program and data stored in the storage unit based on the input from the thermometer 141 or the gas concentration meter 142.

  The cooling control of the fluidized bed drying apparatus 102 by the control means will be described. FIG. 4 is a flowchart of the cooling operation of the fluidized bed drying apparatus.

First, the control means detects the temperature (T: T ₁ , T ₂ ) and gas concentration (X: X ₁ , X ₂ ) from the thermometer 141 or the gas concentration meter 142 (step ST1).
Next, 1) when the detected temperature T is greater than the set value, 2) when the detected gas concentration X is greater than the set value, 3) when the temperature rise dT / dt is greater than the set value, or 4) When it is determined that any one of the cases where the gas concentration increase dX / dt is larger than the set value (step ST2: Yes), the control unit detects a cooling failure of the dry lignite in the cooler 110 and spontaneously ignites. Is determined to be present (step ST3).
On the other hand, when it is determined that none of the above applies (step ST2: No), this control is terminated, and cooling is continued while monitoring is continued.

  Based on the determination in step ST3, the control means controls the gas supply means 151 to add the oxidation-suppressing gas 132 to the cooling air 131 of the countermeasure 1) in order to take measures for improving the cooling failure (step ST3). ST4).

  Whether or not the cooling failure has been improved by supplying the oxidation-suppressing gas 132 is determined in the same manner as in steps ST1 and ST2 (step ST5). If the cooling failure is not detected and it is determined that the cooling failure has been improved (step ST5: Yes). ), It is determined that the cooling is normal, this control is terminated, and the cooling is continued while monitoring.

On the other hand, if the cooling failure is not resolved (step ST5: No), the control unit 2 selects whether to control the discharge of the coolant in the measure 2) or to control the supply of the low-temperature lignite 108L in the measure 3) (step ST6).
This selection is determined in view of temperature conditions and / or gas concentration conditions.

As a result of selection, for example, when the control of the discharge of the dry lignite 108H of measure 2) is selected, the control means sends a command to the lignite discharge means 152 and forcibly cools the internal coolant (the dry lignite 108H) from the cooler 110. Then, it is discharged to the outside (step ST7).
In addition, as a result of selection, for example, when control of supply of the low temperature lignite 108L of measure 3) is selected, the control means sends a command to the low temperature lignite supply means 153, and the cooler 110 supplies the low temperature lignite supply means 153 to the low temperature. The lignite 108L is forcibly charged to cool the temperature inside the cooler 110 (step ST8).
Thus, when it is confirmed that the cooling failure has been improved, the present control is terminated, and the cooling is continued while monitoring.

  According to this fluidized bed drying facility 100A, it is always monitored whether or not there is a cooling failure in the cooler 110, and even if a cooling failure occurs, it is It becomes possible to cool the dry brown coal 108H from the layer drying apparatus 102 without any abnormality.

  Moreover, in this embodiment, although the heat-transfer member as shown in FIG. 1 is abbreviate | omitted, it cannot be overemphasized that it can apply also to the fluid bed drying apparatus which dries directly, without providing a heat-transfer member.

[Second Embodiment]
A fluidized bed drying facility 100B according to the second embodiment of the present embodiment will be described with reference to FIG. As shown in FIG. 5, the fluidized bed drying facility 100B of the present embodiment is divided into a plurality of cooling means in the fluidized bed drying facility 100A shown in FIG. A high temperature cooler 110A and a low temperature cooler 110B on the side close to the fluidized bed drying apparatus 102 are provided.
And the gas supply means 151 which supplies the oxidation suppression gas 132 is provided in the high temperature cooler 110A side, and it is made to operate similarly to 1st Embodiment.

That is, the high temperature dried lignite 108H discharged from the fluidized bed drying apparatus 102 is first cooled by the high temperature cooler 110A.
At this time, if a cooling failure occurs, the cooling failure is improved in the same manner as in the first embodiment. Since the control operation is the same as that of the first embodiment, the description thereof is omitted.
Next, the dried brown coal (medium temperature: 80 ° C., for example) 108M cooled by the high-temperature cooler 110A is sent to the low-temperature cooler 110B, where it is finish-cooled and cooled to 50 ° C. or less.

As described above, in the fluidized bed drying facility 100B of the present embodiment, the cooling means for the dry lignite 108H is divided into two or more stages, and measures for preventing spontaneous ignition are performed on the high temperature cooler 110A side on the high temperature side.
The number of coolers that take measures against spontaneous ignition varies depending on the temperature level of each cooler. However, the number of coolers may be determined by design each time according to the oxidation heat generation rate equation (1) of the processed material, and may have a plurality of stages.
Q = C ₁ (O ₂ ) ⁿ EXP (−C ₂ / T) (1)
Here, C ₁ , C ₂ , and n are coefficients determined by the processed material, O ₂ is the oxygen concentration, and T: the temperature of the processed material.

  Here, the temperature of the cooler is, for example, about 80 ° C. in the case of lignite. This is because, as shown in the temperature rise characteristic diagram of lignite shown in FIG. In the present invention, 80 ° C. is used as a reference, but the temperature threshold may be changed according to the type of coal and the production area.

  Normal operation is continued by detecting changes (temperature, gas concentration) when signs of spontaneous ignition appear, and reducing the heat generation rate or discharging the internal high-temperature lignite and supplying new lignite .

Since the amount of heat generated by oxidation is strongly dependent on temperature, if the environment is sufficiently hot and there is sufficient oxygen in the surroundings and cooling is insufficient, the amount of heat generated by oxidation will be greater than the amount of heat released to the surroundings. The temperature rises rapidly. When the oxidation of lignite accelerates, the generation of CO and CO ₂ gas becomes significant.

  As in this embodiment, by using a plurality of coolers according to the temperature level, the above phenomenon can be easily detected, and more accurate control can be performed.

  By taking measures only for the high-temperature cooler 110A for the high-temperature brown coal 108H, it is possible to reduce the gas supply amount of the oxidation-suppressing gas 132, simplify the equipment / system, and reduce the cost.

  As mentioned above, the fluidized-bed drying apparatus which concerns on this invention is suitable for implementing the countermeasure which can detect the sign of spontaneous combustion in a dry lignite cooler, and can suppress the temperature rise of lignite. .

100A, 100B Fluidized bed drying equipment 101 Brown coal 102 Fluidized bed drying device 103 Heat transfer member 104 Generated steam 105 Dust collector 106 Heat recovery system 107 Fluidized steam 108 Dry brown coal 109 Product coal 110 Cooler 111 Fluidized bed 112 Water treatment unit 113 Drainage 114 Circulating fan 115 Solid component 116 Current plate 131 Cooling air 132 Oxidation suppression gas 141 Thermometer 142 Gas concentration meter 151 Gas supply means 152 Brown coal discharge means 153 Low-temperature lignite supply means 200 Coal gasification combined power generation system 201a Pulverized coal 202 Gasification Gas 203 Coal gasifier 204 Gas turbine (GT)
205 Turbine exhaust gas 206 Waste heat recovery boiler (HRSG)
207 Steam 208 Steam turbine (ST)
209 Generator (G)
210 Mil 211 Cyclone 212 Gas purification device 213 Combustor 214 Combustion gas 215 Exhaust gas 217 Chimney 218 Condenser 219 Air 220 Compressor 221 Air separation device (ASU)
A Superheated steam B Condensate F Free board

Claims (4)

In a fluidized bed drying facility for flowing and drying a material to be dried supplied to the fluidized bed drying device by supplying a fluidized gas to the fluidized bed drying device,
A cooling means for cooling the object to be dried after cooling with cooling air, and detecting means for either or both of a thermometer for detecting the internal temperature and a gas concentration meter for detecting the internal gas concentration;
When temperature information or gas concentration information input by the detection means is larger than a set value, a cooling failure of the object to be dried is detected, and control is performed to add an oxidation suppression gas to the cooling air as a countermeasure for cooling failure improvement. Control means;
A fluidized bed drying facility comprising: In a fluidized bed drying facility for flowing and drying a material to be dried supplied to the fluidized bed drying device by supplying a fluidized gas to the fluidized bed drying device,
The cooling means is divided into a plurality of cooling means according to the temperature of the object to be dried,
Thermometer or internal gas concentration for detecting the internal temperature provided in the high temperature cooling means for cooling the high temperature dry matter discharged from the fluidized bed drying apparatus, in the cooling means for cooling the dry dry matter with cooling air Either or both of the gas concentration meter detecting means for detecting
When temperature information or gas concentration information input by the detection means is larger than a set value, a cooling failure of the object to be dried is detected, and control is performed to add an oxidation suppression gas to the cooling air as a countermeasure for cooling failure improvement. And a fluidized bed drying facility. In claim 1 or 2,
If the cooling failure is not improved even by controlling the addition of the oxidation-suppressing gas, the control means controls either the discharge of the cooling material or the supply of the low-temperature to-be-dried material as a cooling failure improvement measure. Fluidized bed drying equipment. In claim 1 or 2,
A fluidized bed drying facility characterized in that the exhaust gas line exhausted from the cooling means has either one or both of a thermometer for detecting the line internal temperature and a gas concentration meter for detecting the gas concentration inside the line. .

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