JPH043806A - Pulverized coal supplying device - Google Patents

Abstract

PURPOSE:To prevent the development of bridging in a pulverized coal storage vessel without using nitrogen gas by drying the pulverized coal and transporting it after its drying to pulverized coal storage means by the combustion gas and cooling and dehydrating the combustion gas after its transportation of the pulverized coal and then pressurizing the combustion gas to supply it to the pulverized coal storage means. CONSTITUTION:The combustion gas that is produced in a combustion furnace 4 is mixed with combustion gas that is sent out from a blower 11 as it is cooled and dehydrated and sent to a mill 3 to dry the pulverized coal and at the same time the dried pulverized coal is temporarily sent to and stored in a pulverized coal bin 5. The combustion gas sent to the pulverized coal bin goes through a bag filter 6 and part of it goes as the recycle gas through a heat exchanger 18 and it is cooled by a cooler 9 and introduced into a drain pot 10 and dehydrated there. Next, it is pressurized by a blower 11 and part of it is supplied to the lower, tapered section 7 of the pulverized coal bin 5 via an aeration pipe passage 20. With this arrangement the inside of the pulverized coal bin 5 has the atmosphere of inert gas so that natural ignition is suppressed and the bridging is prevented.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an apparatus for finely pulverizing, drying, and supplying coal, and particularly relates to a pulverized coal supply apparatus that uses inert gas for storing and transporting pulverized coal. .

[Conventional technology]

FIG. 2 shows the main configuration of a conventionally known apparatus for supplying pulverized coal to a pressurized reaction vessel for coal gasification or the like.

In the apparatus shown in the figure, coal in a coal hopper 1 is sent from a feeder 2 to a mill 3, where it is pulverized into pulverized coal. This pulverized coal is dried by air preheated by a boiler or other means, transported, and temporarily stored in a pulverized coal bin 5.

Next, it is sent to a lock hopper 14 using an inert gas such as nitrogen, and after a pressurizing operation, it is supplied to a pressurizing reactor 16 such as a coal gasification furnace.

What is important in this method is that when storing pulverized coal after drying, there is a risk that coal will spontaneously ignite in an oxygen-containing atmosphere, so it is important to economically suppress the occurrence of this spontaneous ignition phenomenon. It is to be. Conventionally known technology involves supplying and sealing an inert gas such as nitrogen into a storage container, but in this case, it is necessary to constantly supply nitrogen, which requires a large amount of nitrogen to be prepared in the plant. It is extremely uneconomical to do so.

On the other hand, when pulverized coal is left still in a storage container, bridging occurs, and as a countermeasure against this bridging, mechanical or airage bombardment using nitrogen or the like is performed, and this also requires an inert gas such as nitrogen.

[Problem to be solved by the invention]

As mentioned above, the conventional technology requires a large amount of inert gas such as nitrogen, and also requires the installation of a device to generate this nitrogen gas, so it is not necessarily an economical pulverized coal supply device. .

In addition, in the supply system to a pressurized reactor such as a pressurized coal gasifier, a large amount of nitrogen is required for the pressure increase operation in the lock hopper 14, and in order to recover and reuse it, a recycling device is required. and power, and it is necessary to reduce the amount of nitrogen used.

An object of the present invention is to deal with the occurrence of bridging within a pulverized coal storage container without using nitrogen.

[Means to solve the problem]

The above-mentioned problem is to solve the problem of pulverized coal comprising a pulverizing means for pulverizing coal into pulverized coal, a drying means for drying the pulverized coal with hot air, and a pulverized coal storage means for storing the dried pulverized coal. The supply device includes a combustion furnace that generates combustion gas and supplies the same as hot air to the drying means through a hot air pipe, a cooling means that cools the combustion gas used for drying the pulverized coal, and a cooling means that cools the combustion gas used for drying the pulverized coal. a dehydrating means for dehydrating the used combustion gas; a first pressurizing means for pressurizing the cooled and dehydrated combustion gas; and an aeration pipe communicating the outlet of the first pressurizing means and the pulverized coal storage means. This is achieved by providing a path.

The above object is also achieved by the pulverized coal supply device according to claim 1, wherein the first pressurizing means outlet and the hot air pipe are communicated with each other.

The above problem is also solved by providing a plurality of pulverized coal storage means for pressurized supply sequentially connected to the pulverized coal storage means via a pulverized coal conveying pipe, and connecting the first pressurizing means outlet and the pulverized coal This can also be achieved by the pulverized coal supply device according to claim 1 or 2, which communicates with the conveyance pipe.

The above problem is also solved by connecting a second pressurizing means connected to the dewatering means, an outlet of the second pressurizing means, and a pulverized coal storage means for pressurized supply through a valve. This can also be achieved by the pulverized coal supply device according to any one of claims 1 to 3, which includes a sealing conduit.

The above-mentioned problem is further solved by a heat exchanger and/or a heat exchanger in which the combustion gas before passing through the cooling means is used as the heating side gas and the gas after passing through the second pressurizing means is used as the heated side gas. This can also be achieved by the pulverized coal supply device according to claim 4, which is provided with a storage container.

The above problem can also be solved by forming the lower outer wall of the pulverized coal storage container into a double wall, dividing the inside of the double wall into a plurality of sections, and having a plurality of openings in the inner wall constituting the double wall for each section. This is also achieved by providing holes and at least one gas inlet in each compartment in the outer wall.

[Effect]

The high temperature combustion gas generated in the combustion furnace is supplied to the drying means through the hot air pipe to dry the pulverized coal.

Since the oxygen content in the combustion gas is about 1 to 2%, the temperature of the combustion gas supplied to the drying means can be made higher than in the case of air drying, and the drying efficiency is high.

The dried pulverized coal is transported to the pulverized coal storage means by the combustion gas after drying the pulverized coal. After the pulverized coal has been transported, the combustion gas is cooled by a cooling means, and further water taken from the pulverized coal is dehydrated by a dehydrating means. The dehydrated combustion gas is pressurized by the first pressurizing means and supplied to the pulverized coal storage means through the aeration pipe, thereby destroying the pulverized coal bridges and suppressing the generation of bridges within the pulverized coal storage means. used for.

By supplying a portion of the combustion gas pressurized by the first pressurizing means to the hot air pipe, the high temperature combustion gas generated in the combustion furnace is cooled, and the amount of combustion gas generated in the combustion furnace is is reduced.

When a plurality of pulverized coal storage means for supplying pulverized coal under pressure are provided, if the outlet of the first pressurizing means and the pulverized coal conveyance pipe are communicated, the pressurized combustion gas is A part of the pulverized coal can be used for transporting the pulverized coal to the pulverized coal storage means, thereby reducing the amount of inert gas used.

When a pulverized coal storage means for supplying pulverized coal under pressure is provided, the second pressurizing means stores the dehydrated combustion gas,
After pressurization, the pulverized coal is supplied to the pulverized coal storage means for pressurized supply for sealing and pressurization, thereby reducing the amount of inert gas used.

The heat exchanger installed in the seal pipe heats and raises the temperature of the gas flowing through the seal pipe and supplies it to the pressurized pulverized coal storage means.

The amount of inert gas used for pressurization is reduced, and the pulverized coal is re-dried and preheated.

Since the storage container temporarily stores the dehydrated combustion gas, even if the amount of combustion gas supplied to the pulverized coal storage means for pressurized supply changes, the amount of combustion in the combustion furnace does not need to be changed.

〔Example〕

The gas generated in the combustion furnace is mixed with recycled gas, cooled to a temperature that does not cause pulverized coal to ignite, and then introduced into the mill. The gas introduced into the mill dries the pulverized coal and transports the pulverized coal to the pulverized coal bin. Since the transported gas contains a large amount of water taken from the pulverized coal, it is dedusted in a bag filter, cooled and dehydrated, and recycled as drying gas through a recycling pipe. This recycling keeps the oxygen content low during mill drying, increases the mill inlet temperature of the drying gas supplied to the mill, increases drying efficiency, and reduces the risk of dust explosions. . On the other hand, the dehydrated gas is supplied from the aeration pipe to the lower part of the pulverized coal bin as a seal gas, which also serves as aeration gas. The gas supplied to the bottle is only circulated and does not add to the overall gas volume. Due to its low oxygen content, it can also be used as an alternative gas for lock hoppers for supplying pressurized reactors. Therefore, there is almost no need to use an inert gas such as nitrogen, which has been conventionally used.

Hereinafter, the present invention will be described in detail with reference to FIG. 1. The pulverized coal supply device shown in FIG. ,
The coal feeder 2 receives the supply of coal and pulverizes the coal to produce pulverized coal, and connects it to a mill 3 which is a drying means and pulverizing means for drying the produced pulverized coal. A pulverized coal bin 5 is provided as a pulverized coal storage means, a bag filter 6 is provided on the top of the pulverized coal bin 5, and the pulverized coal that is connected to the outlet of the bag filter 6 and passed through the bag filter 6 is provided. Heat exchanger 18 that uses combustion gas as heating side gas
, a cooler 9 which is a cooling means whose inlet of the gas to be cooled is connected to the gas outlet on the heating side of the heat exchanger 18, and a drain pot 10 which is a dehydration means connected to the outlet of the gas to be cooled of the cooler 9. , a blower 11 that is connected to the drain pot 10 and is a first pressurizing means for blowing the gas (cooled and dehydrated combustion gas) in the drain pot 10 under pressure; and the blower 11
an aeration pipe 20 that communicates the outlet side of the pulverized coal bin with the lower tapered portion 7 of the pulverized coal bin 5; and a combustion furnace 4 that is connected to the mill 3 via a hot air pipe 22 and supplies combustion gas to the mill 3. , a compressor 12 connected to the drain pot 10 and serving as a second pressurizing means for pressurizing the gas in the drain pot 10, a storage container 17 connected to the outlet side of the compressor 12, and the pulverized coal bin 5. quantitative feeder 8
The receiver connected to the pulverized coal conveying pipe 23 via the hopper 1
3, a lock hopper 14 whose receiver is connected to the pulverized coal outlet side of the hopper 13 via a valve, and a supply hopper 15 connected to the pulverized coal outlet side of the lock hopper 14 via a valve;
a pulverized coal supply pipe 24 that connects the pulverized coal outlet side of the supply hopper 15 and the pressurized reactor 16 via a quantitative feeder 8;
The outlet of the storage container 17 and the heated gas inlet side of the heat exchanger 18 are communicated, and the heated gas outlet side of the heat exchanger 18 and the lock hopper 14° supply hopper 15 are communicated via a valve. The sealing pipe line 21, the bag filter 6, the heated gas side of the heat exchanger 18, the cooled gas side of the cooler 9, the drain pot 10. Blower 11. The recycle pipe 19 is configured to include a recycle pipe 19 that sequentially connects the hot air pipes 22. The recycling pipe 19 also connects the outlet of the blower 11 and the pulverized coal conveying pipe 23 on the exit side of the quantitative feeder 8.

The lock hopper 14. The supply hopper 15 is a pulverized coal storage means for supplying pulverized coal under pressure.

The operation of the apparatus having the above configuration will be explained below.

The coal stored in the coal hopper 1 is supplied in a fixed amount by a coal feeder 2 to a mill 3, where it is crushed and pulverized.

In the combustion furnace 4, high temperature combustion gas is generated. The oxygen content in this combustion gas is about 1 to 2%.

Further, the temperature of this combustion gas is usually around 1000° C., and if this high temperature combustion gas is directly supplied to the mill 3, there is a risk of ignition of the carbonized coal. Therefore, the combustion gas generated in the combustion furnace 4 is transferred from the blower 11 to the recycling pipe 1.
9, the coal is mixed with the cooled and dehydrated combustion gas and carbonized.

It is brought to a temperature below the ignition temperature and sent to the mill 3. The combustion gas sent to the mill 3 dries and transports the pulverized coal, but since the oxygen content in the combustion gas is low, the temperature at the time of introduction into the mill 3 is approximately 200 to 250°C. Since the moisture content is low, the drying efficiency in the mill 3 is good.

The dried pulverized coal is sent to the pulverized coal bin 5 together with the introduced combustion gas and temporarily stored.

The temperature of this dry pulverized coal is approximately 80 to 90"C, but since it is dry, spontaneous combustion is likely to occur in an air atmosphere. The combustion gas sent to the pulverized coal bin 5 passes through a bag filter 6. A part of the recycled gas passes through the heating fluid side of the heat exchanger 18, is cooled by the cooler 9, and is then introduced into the drain pot 10.The recycled gas introduced into the drain pot 1° is After being dehydrated, it is pressurized by the blower 11 and a part of it is supplied to the lower taper part 7 of the pulverized coal bin 5 through the aeration pipe 2o.The recycled gas supplied to the lower taper part 7 is The inside of the bottle 5 is made into an inert atmosphere to suppress the occurrence of spontaneous combustion.

The lower tapered section 7 to which recycled gas is supplied has a double structure with inner and outer walls, the double structure is divided into a plurality of sections, and the inner wall has a plurality of holes in each section. is provided. At least one for each section on the exterior wall.
A gas inlet is provided. The recycled gas is sequentially supplied to each section from the gas inlet on the outer wall, and is ejected into the pulverized coal bin 5 from the opening provided in the inner wall to prevent bridge formation within the pulverized coal bin 5. Care has been taken to reduce the amount of gas.

On the other hand, the other part of the recycled gas pressurized by the blower 11 is mixed with the high temperature combustion gas generated in the combustion furnace 4 in the hot air pipe 22, and after lowering the combustion gas temperature as described above. , and is supplied to the mill 3 to dry the pulverized coal in the mill.

The pulverized coal in the pulverized coal bin 5 passes through a quantitative feeder 8 and is conveyed to a hopper 13 by a portion of recycled gas pressurized by a blower 11 . The pulverized coal in the hopper 13 is
It is sent to the supply hopper 15 via the lock hopper 14,
It is then supplied to a pressurized reactor 16 via a quantitative feeder 8.

A portion of the recycled gas dehydrated within the drain bot 10 is pressurized to a predetermined pressure by the compressor 12 and introduced into the storage container 17 . The gas stored in the storage container 17 is sent to the heat exchanger 18 via the aeration pipe line 21 as needed, and after being heated and raised in temperature, the gas is transferred to the lock hopper 14. The gas is sent as a sealing gas to the supply hoppers 15 to increase the pressure in each hopper and prevent the formation of bridges.

According to this embodiment, the combustion gas generated in the combustion furnace dries the pulverized coal in the mill 3 and transports the pulverized coal from the mill 3 to the pulverized coal bin 5. According to this embodiment, the amount of inert gas such as nitrogen can be reduced because the pulverized coal is collected from the pulverized coal bin 5, cooled and dehydrated, and then used as a recycled gas to prevent bridging of the pulverized coal bin 5. The recycled gas is also used to cool the high-temperature combustion gas sent out from the combustion furnace, boost the pressure of the lock hopper and supply hopper, seal, prevent bridge formation, and transport the pulverized coal from the pulverized coal bin 5 to the hopper. Therefore, the amount of inert gas used can be reduced, and an economical pulverized coal supply device can be obtained.

Further, in this embodiment, the combustion furnace has been described as a pulverized coal supply device, but it goes without saying that there is no need to provide a dedicated combustion furnace for the pulverized coal supply device if there is an available combustion device.

〔Effect of the invention〕

According to the present invention, the amount of inert gas such as nitrogen used is reduced, and the cost of manufacturing equipment and recycling equipment for inert gas such as nitrogen can be reduced.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention, and FIG. 2 is a system diagram showing an example of the prior art. 3...Crushing means and drying means (mill), 4...Combustion furnace, pulverized coal storage means (pulverized coal bin), 9...Cooling means (cooler), 10...Dehydration means (Drainbot)
, 11... First pressurizing means (blower), 12... Second pressurizing means (compressor), 14.15... Pulverized coal storage means for pressurized supply (lock hopper, supply hopper), 17... storage container, 18... heat exchanger, 1
9... Recycling pipe line, 20... Aeration pipe line, 21... Seal pipe line, 22... Hot air pipe line, 23
...Pulverized coal conveyance pipeline.

Claims (1)

[Claims] 1. Comprising a pulverizing means for pulverizing coal into pulverized coal, a drying means for drying the pulverized coal with hot air, and a pulverized coal storage means for storing the dried pulverized coal. The pulverized coal supply device includes: a combustion furnace that generates combustion gas and supplies it as hot air to the drying means through a hot air pipe; a cooling means that cools the combustion gas used to dry the pulverized coal; a first pressurizing means for pressurizing the cooled and dehydrated combustion gas;
A pulverized coal supply device comprising an aeration pipe line that communicates the outlet of the first pressurizing means with the pulverized coal storage means. 2. The pulverized coal supply device according to claim 1, wherein the outlet of the first pressurizing means and the hot air pipe are communicated with each other. 3. A plurality of pulverized coal storage means for pressurized supply are sequentially connected to the pulverized coal storage means via pulverized coal conveyance pipes, and the outlet of the first pressurizing means and the pulverized coal conveyance The pulverized coal supply device according to claim 1 or 2, wherein the pulverized coal supply device is in communication with a conduit. 4. a second pressurizing means connected to the dehydration means;
Any one of claims 1 to 3 further comprising a sealing conduit that communicates the outlet of the second pressurizing means with the pulverized coal storage means for pressurized supply via a valve. pulverized coal feeding equipment. 5. A heat exchanger and/or a storage container are interposed in the sealing conduit, in which the combustion gas before passing through the cooling means is used as the heating side gas, and the gas after passing through the second pressurizing means is used as the heated side gas. The pulverized coal supply device according to claim 4, characterized in that: 6. A container for storing pulverized coal, in which the lower outer wall of the container is formed into a double wall, the inside of the double wall is divided into a plurality of compartments, and the inner wall constituting the double wall has the compartments. A pulverized coal storage vessel having a plurality of apertures in each compartment and at least one gas inlet in each compartment in the outer wall.