JPH09178356A - Unburnt matter content reducing apparatus for coal ash and incinerated ash fluidized bed cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to distribute the heat quantity discharged or transferred to be recovered during fluidizing and cooling in or out of an apparatus system by receiving incinerated ash (low unburnt content coal ash after reburning) having large heat quantity. SOLUTION: This incinerated ash fluidized bed cooler Y comprises an incinerated ash mounting means 2' mounted in the bottom of a body 21, an air chamber 3' provided under the means 2', an air supply means 6' communicating with the chamber 3', a cold heat means 5 provided above the means 2' to introduce it out of the body 21 into a tube and disposed in a zigzag manner between the fluidized cooling layers, and an incinerated ash discharge and recovering means 7d provided at the sidewall of the fluidized upper layer area. Further, the cooler Y is included in the system as a coal ash fluidized cooler 21 to constitute the unburnt content reducing apparatus for the coal ash.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a good cement admixture that reduces the content of unburned matter remaining in coal ash (object to be treated) discharged from a pulverized coal combustion boiler by reducing the content thereof. A device for reducing the unburned content of coal ash for reforming it to a usable state, and an independent device configuration that accepts incineration ash with a large amount of heat from the outside, fluidizes it, and cools the amount of heat discharged or transferred during this period. To an incineration ash fluidized bed cooling device that can be distributed to the device system of The incineration ash means the combustion residue (combustion ash) of the powder to be treated.

[0002]

2. Description of the Related Art Coal ash discharged from a pulverized coal combustion boiler has been approved for use as a cement admixture.

However, since coal ash obtained by burning general pulverized coal has an unburned content of 3 to 6%, the amount of adsorbed methylene blue which deteriorates the quality of the cement admixture increases, and the cement admixture remains as it is. When used as a material, there has been a problem that the air entrainment material (AE material) mixed in the cement is adsorbed by the unburned components and the air amount becomes difficult to manage.

Therefore, at present, this coal ash is
Are processed in the manner shown in FIG. Landfill. Classifying with a separator to remove high unburned coal ash particles and reduce the overall unburned content to improve the quality of cement admixture. Coal with good flammability is used to prevent the generation of residual unburned matter and reduce the content of unburned matter in coal ash to reform it into a high quality cement admixture.

[0005]

However, the above-described conventional processing has the following problems (a) to (c). (B) There is a limit to the amount of waste that can be landfilled, and unused coal ash becomes useless waste. (B) In order to remove high unburned coal ash particles by classifying with a separator, an expensive separator and time (man-hour) for classifying are required. (C) The use of coal having good combustibility increases the operating cost of the boiler.

Under these circumstances, the present inventors have conducted researches on high quality (reforming) in order to effectively utilize a large amount of coal ash discharged from a coal-fired power plant. Then, we have developed a new combustion method using a fluidized bed combustion furnace to reduce the unburned matter remaining in the coal ash. This result has been previously proposed by the present applicant as "a method for reducing unburned content of coal ash and a coal ash fluidized bed combustion furnace" (Japanese Patent Application No. 7-57948; prior art).

In the coal ash-containing unburned-content reducing apparatus system including the prior application technology, a cooling device for cooling and recovering a large amount of heat of low unburned-content coal ash discharged from a coal ash fluidized bed combustion furnace. (System) was required, and proposals for the flow sheet were requested as well as an efficient heat utilization mode in which both were linked.

From this, a coal ash fluidized bed cooler in which the low unburned coal ash after combustion treatment is the object to be treated is considered. On the other hand, this coal ash fluidized bed cooler is not limited to coal ash and may be any incinerated ash (powder) as a treated object, and is separable from the above-mentioned unburned coal content reduction device system of coal ash. It is preferable that the above-mentioned apparatus configuration (incinerator ash fluidized cooling apparatus) is adopted.

That is, the unburned matter remaining in the coal ash (object to be treated) discharged from the pulverized coal combustion boiler is burned again to reduce its content and reform it so that it can be used as a good cement admixture. A device for reducing unburned content of coal ash,
In addition, it is expected to propose an incinerator ash fluidized bed cooling device that can receive the incinerated ash having a large heat quantity from the outside with the independent equipment configuration, fluidize it, and distribute the heat quantity discharged or heat-transfer recovered to other equipment systems. It

[0010]

In order to solve the above-mentioned problems, the present invention is an apparatus for reducing the content of unburned coal ash, which is a means for loading coal ash installed in the bottom of a furnace, and a means for loading this coal ash. An air chamber provided below the placing means, a combustion-supporting gas supply means that communicates with this air chamber, a coal ash supply means that communicates with the outside of the furnace, and a furnace during fluid combustion that includes preheating after charging the coal ash. A coal ash fluidized bed combustion furnace having combustion control means for maintaining the temperature in the self-combustion temperature range of coal ash, and a treated material discharge means provided in multiple stages on the furnace wall in the upper fluidized zone; A coal ash fluidized bed cooler configured to receive and cool the discharged low unburned coal ash through a cooling and heating means into a fluidized cooling bed maintained in a low temperature range, and to discharge and recover the treated low unburned coal ash. And; mixed exhaust gas from the coal ash fluidized bed combustion furnace and the coal ash fluidized bed cooler The refrigerant of the serial thermal means and piping respectively introduced and is characterized by comprising a heat recovery boiler so as to heat exchange between them.

Further, there is provided an incineration ash fluidized bed cooling device which receives incineration ash having a large heat quantity from the outside and fluidizes and cools it, and at the same time can distribute the amount of heat discharged or heat-transfer recovered to other device systems. An incineration ash placing means installed in the bottom of the main body, and an air chamber provided below the incinerator ash placing means,
An air supply means communicating with the air chamber, a cooling means provided above the incineration ash placing means and arranged in a meandering manner between the fluid cooling layers by introducing a pipe from the outside of the main body, and provided on the side wall of the fluid upper layer region. The incinerated ash discharge recovery means is provided.

Here, the incineration ash placing means is 1 to 100 μm.
It is a perforated plate in which a large number of fine holes having a diameter are formed.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The apparatus for reducing unburned content of coal ash according to the present invention mainly comprises the above-mentioned coal ash fluidized bed combustion furnace, coal ash fluidized bed cooler and heat recovery boiler, and connects these constituent elements. And has a systematic processing step layout (flow sheet).

Then, the unburned residual coal ash is charged into the coal ash fluidized bed combustion furnace to burn the unburned content in the coal ash within the self-combustion temperature range, and an exhaust pipe provided on the furnace wall in the upper region of the fluidized bed. The low unburned coal ash after treatment is discharged from the tank and is received by the fluidized cooling bed of the coal ash fluidized bed cooler that is maintained in the low temperature range through the cooling and heating means. While discharging and recovering, the refrigerant (hot water) discharged from the cooling / heating means is introduced into the heat recovery boiler by piping, and the mixed flue gas (combustion exhaust gas and combustion flue gas of the coal ash fluidized bed combustion furnace and coal ash fluidized bed cooler introduced from another system The high temperature water obtained by exchanging heat with the high temperature air) is separately used.

In a coal ash fluidized bed combustion furnace, unburned residual coal ash (object to be treated) is charged on a perforated plate in the furnace and preheated to a self-combustion temperature range (650 to 850 ° C.) by combustion means, The supporting gas is supplied to the lower side of the perforated plate in the furnace by the supporting gas supply means, the supporting gas is increased from the fine holes of the perforated plate between the particles of the coal ash, and the coal ash is fluidized and burned. The unburned matter remaining in the coal ash by means of 650 to 850 ° C.
To reduce the unburned content of the coal ash to about 1% or less, and reform it to a low unburned coal ash.

In the coal ash fluidized bed cooler, low unburned coal ash having a large amount of heat after the above treatment is received as an object to be treated, and is fluidized and cooled through a cooling means to be discharged / collected. The low unburned coal ash thus obtained can be used as a high-quality cement admixture because it has a small amount of adsorbed methylene blue.

Here, the coal ash fluidized bed cooler has an independent device structure and can be separated as an incineration ash fluidized bed cooling device, and an incineration ash placing means composed of a perforated plate installed in the bottom of the main body is provided. , An air chamber provided below the incineration ash placement means, an air supply means communicating with this air chamber, and a pipe provided from above the main body provided above the incineration ash placement means to meander between the fluid cooling layers. The incineration ash discharge recovery means provided on the side wall of the fluidized upper layer area is provided, and the incineration ash having a large heat amount is received from the outside to be fluidized and cooled, and discharged during this period. The amount of heat recovered by heat transfer can be distributed to other device systems.

In the heat recovery boiler, the refrigerant (warm water) discharged from the cooling / heating means of the coal ash fluidized bed cooler is introduced into the pipe, and the mixed exhaust gas of the coal ash fluidized bed combustion furnace and the coal ash fluidized bed cooler introduced from another system is introduced. Heat is exchanged with (combustion exhaust gas and high temperature air), and the high temperature water obtained is used separately (inside or outside the system).

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a flow sheet showing an apparatus for reducing unburned content of coal ash, which is an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining a coal ash fluidized bed cooler (or incineration ash fluidized bed cooling device).

As shown in FIG. 1, the coal ash-containing unburned-content reducing device (X) receives the unburned-content residual coal ash (processed material) from the coal ash supply means (4) and fluidizes and burns it. Ash fluidized bed combustion furnace (1), coal ash fluidized bed cooler (21) that receives and cools the low unburned residual coal ash after combustion treatment discharged from the combustion furnace (1), and discharges from these Cyclone (23), heat recovery boiler (24), dust collector (25), desulfurization and denitration device (26) as post-treatment means for combustion exhaust gas (16) and high temperature air (15), and each component described above. It is composed of each processing system (pipe) that connects the two.

Here, the coal ash supply means (4) is provided with a powder preparation means (not shown, a powder mixture supply device as an independent device) to pretreat unburned residual coal ash and burn it. You may make it accept the mixture [unburned-residual-residual-coal-ash and an auxiliary combustion material] which adjusted the component (heating value) as a to-be-processed object.

In this pretreatment, when the unburned residual coal ash of about 2 to 3% is treated, the temperature in the furnace is set to a desired value of 650 to 85.
It is possible to adjust the combustion components so as to maintain the temperature at 0 ° C. (self-combustion temperature range) to increase the calorific value at the time of combustion (corresponding to the calorific value of coal ash with an unburned content ratio of about 5 to 6%). Useful when requested.

Further, as shown in FIG. 2, the coal ash fluidized bed cooler (21) has a perforated plate (2 ') installed in the bottom of the main body.
And an air chamber (3 ') provided below the perforated plate (2') and an air supply pipe (6 ') communicating with this air chamber (3'), and provided above the perforated plate (2 '). A cooling pipe (5) which is introduced from outside the main body (21) and meanders between the fluid cooling layers.
And a discharge pipe (7d) provided on the side wall of the fluidized upper layer region and an exhaust pipe (8b) at the top.

The high-temperature air (15) flowing through the exhaust pipe (8b) of the coal ash fluidized bed cooler (21) is a combustion exhaust gas (15a) flowing through the exhaust pipe (8a) of the coal ash fluidized bed combustion furnace (1). 1
6) It joins and becomes mixed exhaust gas (17) and cyclone (2
Exhaust pipe (8c) from cyclone (23) introduced in 3)
The mixed exhaust gas (17) flowing through the heat recovery boiler (24) is introduced into the heat recovery boiler (24). The discharge side of the cooling pipe (5) is connected to the heat exchanger (11) in the heat recovery boiler (24).
[Fig. 1]

The coal ash fluidized bed cooler (21) can be separated as an independent incineration ash fluidized bed cooling device (Y).

Then, the treatment process in the coal ash-containing unburned-content reducing apparatus (X) will be described.

First, the perforated plate (2) in the combustion furnace (1) is passed through a coal ash supply pipe (not shown) of the coal ash supply device (22).
The coal ash (12) is preheated (and burned) by being supplied (supplied) to the top and igniting the burner by the preheating device (10).

When the preheating temperature reaches 650 to 850 ° C. (the self-combustion temperature range of coal ash), the preheating device (10) is stopped and switched to self-combustion, and air (3) is supplied from the air supply pipe (6) to the air chamber (3). 13) is fed and blown from below the perforated plate (2) to raise the interparticles of the coal ash (12) and fluidize the coal ash (12), which remains in the coal ash (12). Burn unburned components (self-burning).

At this time, the temperature in the furnace (fluidized bed temperature) rises due to combustion heat, but is controlled (temperature control) to 650 to 850 ° C. by dropping and supplying new coal ash. That is, during combustion, the temperature inside the furnace is detected by each thermometer (not shown). If this temperature decreases, the supply amount of air (13) is reduced, and if the temperature rises, the supply amount of air (13) is reduced. To maintain a combustion temperature of 650-850 ° C.
This is a so-called continuous operation in which the temperature inside the furnace is controlled as needed by adjusting the supply of coal ash (12) and air (13).

FIG. 3 shows a data plot of fluidized bed temperature and unburned carbon content. Here, the unburned component content of 5 to 6% (previously described) before combustion is due to the combustion treatment of 650 to 850 ° C.
It can be confirmed that it decreases to 0.4 to 1.8%.

The low unburned coal ash (12a) rising to the upper fluidized zone in the furnace is taken out (recovered) by changing the discharge position according to the unburned content. Is discharged from the upper discharge pipe (7b) or the lower discharge pipe (7a) provided on the furnace wall to the porous plate (2 ') in the coal ash fluidized bed cooler (21) via the supply pipe (7c).

In the coal ash fluidized bed cooler (21), the air (13 ') fed from below the perforated plate (2') is supplied with a low unburned content from fine holes (not shown) of the perforated plate (2 '). Coal ash (12
While increasing the number of particles in a), the cooling water (14) is circulated in the cooling pipe (5) arranged in a meandering manner between the fluid cooling layers to fluidly cool the low unburned coal ash (12a). . Then, the low unburned coal ash (12a) is discharged and collected to the outside.

Further, the hot water (14 ') which has been heated in exchange for heat-cooling the low unburned coal ash (12a) is used separately in the system or outside the system through heat exchange in the heat recovery boiler (24) described later. To be done.

The high temperature air (15) discharged from the coal ash fluidized bed cooler (21) joins with the combustion exhaust gas (16) discharged from the combustion furnace (1) in the middle of the path to form a mixed exhaust gas (17). , Sent to a downstream cyclone (23).

In the cyclone (23), mixed exhaust gas (17)
The low unburned coal ash (12a) containing dust inside is removed and discharged downward, and the mixed exhaust gas (17) after dust removal is exhausted (8
It is sent to the heat recovery boiler (24) via c).

On the other hand, the cooling pipe (5) on the discharge side of the coal ash fluidized bed cooler (21) is connected to the heat recovery boiler (24), and the cooling water (warm water) (14 ') is connected to the heat recovery boiler (24). (4) is introduced into the heat exchanger (11) and the heat is exchanged with the mixed exhaust gas (17).

In this way, the cooling water (warm water) (14 ') is further heated to become high-temperature water [or steam] (14a), which is separately used inside or outside the system.

The mixed exhaust gas (17) after heat recovery is introduced into the dust collector (25) to remove dust again, and then SO _X and NO _X contained in the heat recovery boiler (24) for the desulfurization / denitrification device are removed. After removal, it is released into the atmosphere.

[0040]

EFFECTS OF THE INVENTION The present invention is constituted as described above, and according to the present invention, good combustion (treatment) is maintained and the unburned content of coal ash is reduced to about 1% or less. Since unburned coal ash can be obtained, it can be effectively used as a high-quality cement admixture.

Further, since a large amount of heat generated in the system is recovered by heat including a cooling process and can be separately used in the system or outside the system,
It can contribute to energy saving.

Further, since the coal ash fluidized bed cooler has an independent device configuration and is separable from the device system including the combustion furnace, it is generally used as a fluidized bed cooling device using incineration ash as an object to be treated. be able to.

[Brief description of the drawings]

FIG. 1 is a flow sheet illustrating an apparatus for reducing unburned content of coal ash, which is an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating a coal ash fluidized bed cooler (or an incineration ash fluidized bed cooling device) of an example.

FIG. 3 is a data plot showing a fluidized bed temperature (combustion temperature of coal ash) VS. unburned matter content of a fluidized bed combustion furnace in a coal ash fluidized bed combustion apparatus of an example.

[Explanation of symbols]

 1 Combustion furnace (Coal ash fluidized bed combustion furnace) 2; 2 'Perforated plate (Coal ash mounting means; Incineration ash mounting means) 3; 3' Air chamber 5 Cooling pipe (cooling means) 6; 6 'Air supply pipe (Combustion gas supply means; air supply means) 7a Lower discharge pipe (processed material discharge means) 7b Upper discharge pipe (processed material discharge means) 7c Supply pipe 7d Discharge pipe (processed material discharge recovery means) 8a Exhaust pipe (coal ash) Fluidized bed combustion furnace) 8b Exhaust pipe (Coal ash Fluidized bed cooler) 8c Exhaust pipe (Cyclone) 10 Preheating device (Combustion control means) 12 Coal ash (Unburned residual coal ash) 12a Low unburned coal ash 13; 13 'Air [flow path] 14; 14' Refrigerant (cooling water; hot water) [flow path] 14a High-temperature water [flow path] 15 High-temperature air [flow path] 16 Combustion exhaust gas [flow path] 17 Mixed exhaust gas [flow path] 21 Coal ash fluidized bed cooler 22 Coal ash supply device (coal ash supply means) 23 Cyclone 24 Heat recovery boiler 25 Dust collector 26 Desulfurization denitration device X Coal ash content燃分 reducing device Y incineration ash fluidized bed cooler

Claims (3)

[Claims] 1. An unburned residual coal ash is received in a combustion furnace main body so that the unburned residual coal ash discharged as incineration ash from a pulverized coal boiler is burned again for reforming treatment. In a coal ash content unburned matter reduction apparatus including a coal ash fluidized bed combustion furnace that fluidizes and burns at, a coal ash loading means installed inside the furnace bottom and an air chamber provided below the coal ash loading means And, the combustion-supporting gas supply means that communicates with this air chamber, the coal ash supply means that communicates with the outside of the furnace, and the furnace temperature during fluidized combustion including preheating after charging the coal ash within the self-combustion temperature range of the coal ash. A coal ash fluidized bed combustion furnace having a combustion control means for holding it, and a treated material discharging means provided in multiple stages on the furnace wall in the upper fluidized zone; a low unburned coal ash discharged from the coal ash fluidized bed combustion furnace Is received in the fluidized cooling bed that is kept in the low temperature range via the cooling / heating means. And a coal ash fluidized bed cooler adapted to discharge and recover low unburned coal ash after treatment; a mixed exhaust gas of the coal ash fluidized bed combustion furnace and the coal ash fluidized bed cooler and a refrigerant of the cooling means. An apparatus for reducing unburned content of coal ash, comprising: a heat recovery boiler that is introduced into each of the pipes and exchanges heat between them. 2. The incineration ash fluidized bed cooling device receives incineration ash having a large amount of heat from the outside to perform fluid cooling, and at the same time, the amount of heat discharged or recovered by heat transfer can be distributed to another device system. A fluidized bed cooling device, in which an incineration ash placing means installed in a bottom portion of a main body, an air chamber provided below the incinerator ash placing means, an air supply means communicating with the air chamber, and an incineration ash A cooling means provided above the placing means and arranged in a meandering manner between the fluid cooling layers by introducing pipes from the outside of the main body; and an incineration ash discharge recovery means provided on the side wall of the fluidized upper layer area. Characterized incinerator ash fluidized bed cooling system. 3. The incineration ash placing means is a perforated plate,
The incinerator ash fluidized bed cooling device according to claim 2, wherein a large number of fine holes having a diameter of 100 μm are formed.