JP2553734B2 - Pulverized coal feeder - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for pulverizing and drying coal and supplying it, and more particularly to an apparatus for supplying pulverized coal that uses an inert gas for storage and transportation of pulverized coal. .

[Conventional technology]

FIG. 2 shows the main structure 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, the coal in the coal hopper 1 is sent from the feeder 2 to the mill 3 and pulverized into pulverized coal. This pulverized coal is dried by air preheated by a boiler or other means,
It is transported and temporarily stored in the pulverized coal bottle 5. Then, it is sent to the lock hopper 14 by an inert gas such as nitrogen, and after the pressurizing operation, it is supplied to the pressurizing reactor 16 such as a coal gasifier.

What is important in such a method is that when storing pulverized coal after drying, coal may cause a spontaneous combustion phenomenon in an atmosphere containing oxygen, and the occurrence of this spontaneous combustion phenomenon is economically suppressed. It is to be. In the conventionally known technology, an inert gas such as nitrogen is supplied and sealed in a storage container. In this case, it is necessary to constantly supply nitrogen, and a large amount of nitrogen is prepared in the plant. It is extremely uneconomical to do.

On the other hand, pulverized coal causes a bridge when it is allowed to stand in the storage container, so mechanical or aeration with nitrogen or the like is performed as a countermeasure against this break, and an inert gas such as nitrogen is also required in this aspect.

[Problems to be Solved by the Invention]

As described above, the prior art requires a large amount of inert gas such as nitrogen, and a device for generating this nitrogen gas must be installed, which is not always an economical pulverized coal supply device. .

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

An object of the present invention is to cope with the generation of bridges in a pulverized coal storage container without using nitrogen.

[Means for solving the problem]

The above-mentioned problems include pulverizing means for pulverizing coal into pulverized coal, drying means for drying the pulverized coal with hot air, and generating combustion gas as hot air to the drying means through a hot air duct. A combustion furnace for supplying, a pulverized coal storage means for storing the dried pulverized coal conveyed to the combustion gas after pulverized coal drying, a cooling means for cooling the combustion gas passing through the pulverized coal storage means, and a cooled A dehydrating means for dehydrating the combustion gas, and a first pressurizing means for pressurizing the cooled and dehydrated combustion gas,
This is achieved by a pulverized coal supply device including an outlet line for communicating the outlet of the first pressurizing means and the lower portion of the pulverized coal storage means.

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

The above-mentioned problem is also provided with a plurality of pulverized coal storage means for pressurizing supply, which are sequentially connected to the pulverized coal storage means via a pulverized coal transport pipeline, and a first pressurizing means outlet and the pulverized coal are provided. It is also achieved by the pulverized coal supply device according to claim 1 or 2, which is in communication with the transfer pipeline.

The above-mentioned problem is also that the second pressurizing means provided in connection with the dehydrating means, the second pressurizing means outlet and the pulverized coal storage means for pressurizing supply are communicated via a valve. It is also achieved by the pulverized coal supply device according to any one of claims 1 to 3, which is provided with a sealing pipeline.

The above-mentioned problem further includes 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 in the sealing pipe line, and / or It is also achieved by the pulverized coal supply device according to claim 4 in which a storage container is interposed.

The above-mentioned problem is also that the lower outer wall of the pulverized coal storage container is a double wall, the inside of the double wall is divided into a plurality of compartments, and a plurality of compartments are formed on each of the inner walls constituting the double wall. This can also be achieved by providing holes and at least one gas blowing port for each section on the outer wall.

[Action]

The high-temperature combustion gas generated in the combustion furnace is supplied to the drying means via the hot air duct to dry the pulverized coal. Since the oxygen content in the combustion gas is approximately 1 to 2%, the temperature of the combustion gas supplied to the drying means can be higher than that in the case of air drying, and the drying efficiency is high.

The pulverized coal after drying is conveyed to the pulverized coal storage means by the combustion gas after drying the pulverized coal. The combustion gas after the pulverized coal is conveyed is cooled by the cooling means, and the water taken from the pulverized coal is dehydrated by the dehydrating means. The dehydrated combustion gas is pressurized by the first pressurizing means and is supplied to the pulverized coal storage means through the aeration pipeline to suppress the destruction of the pulverized coal bridge and the generation of the bridge in the pulverized coal storage means. Used for.

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

When a plurality of pulverized coal storage means for pressurizing and supplying the pulverized coal are provided and the first pressurizing means outlet is in communication with the pulverized coal conveying pipeline, A part of it can be used for transporting the pulverized coal to the pulverized coal storage means, and the amount of inert gas used can be reduced.

When the pulverized coal storage means for pressurizing and supplying the pulverized coal is provided, the second pressurizing means pressurizes the combustion gas after dehydration, and then pressurizes and supplies the pulverized coal. Since it is supplied to the coal storage means for sealing and pressurization, the amount of inert gas used is reduced.

Since the heat exchanger interposed in the seal conduit heats and raises the temperature of the gas flowing in the seal conduit and supplies it to the pulverized coal storage means for supplying under pressure, an inert gas for sealing and pressurization is used. The amount of coal used is reduced, and 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 supplying under pressure is changed, the amount of combustion in the combustion furnace may not be changed.

〔Example〕

The gas generated in the combustion furnace is mixed with the recycled gas, cooled to a temperature at which ignition of pulverized coal does not occur, and then introduced into the mill. The gas introduced into the mill dries the pulverized coal and conveys the pulverized coal to the pulverized coal bottle. Since the gas after transportation contains a large amount of water taken from pulverized coal, it is cooled and dehydrated after dust removal by a bag filter, and is recycled as a drying gas from a recycling pipe. By this recycling, the oxygen content during mill drying can be kept low, the mill inlet temperature of the drying gas supplied to the mill can be raised to improve the drying efficiency, and the risk of dust explosion etc. is reduced. . On the other hand, the dehydrated gas is supplied as a seal gas from the aeration pipe line to the lower part of the pulverized coal pin also as an aeration gas. The gas supplied to the pin is
It only circulates and does not increase the total amount of gas.
Due to its low oxygen content, it can also be used as a substitute gas for the lock hopper for feeding pressurized reactors. Therefore, the inert gas such as nitrogen which has been used in the past can be hardly used.

An embodiment of the present invention will be described below with reference to FIG.
The pulverized coal supply device shown in the figure is a coal hopper 1 and a coal feeder 2 that takes out and conveys coal stored in the coal hopper 1.
And a mill 3 which is a drying means and a crushing means for receiving coal supplied from the coal feeder 2 to pulverize the coal to produce pulverized coal and to dry the produced pulverized coal, and to connect the mill 3. Pulverized coal storage means provided as pulverized coal bin 5,
A bag filter 6 provided above the pulverized coal bottle 5,
A heat exchanger that is connected to the outlet of the bag filter 6 and uses the combustion gas that has passed through the bag filter 6 as the heating side gas.
18, a cooler 9 which is a cooling means having a cooled gas inlet connected to the heating side gas outlet of the heat exchanger 18, and a drain pot which is a dehydrating means connected to the cooled gas outlet of the cooler 9. 10, a blower 11 that is connected to the drain pot 10 and is a first pressurizing unit that blows gas (cooled and dehydrated combustion gas) in the drain pot 10 under pressure, an outlet side of the blower 11, and An aeration pipe line 20 communicating with the lower taper portion 7 of the pulverized coal bottle 5, a combustion furnace 4 connected to the mill 3 via a hot air pipe line 22 for supplying combustion gas to the mill 3, and the drain pot 10 A compressor 12 which is a second pressurizing means connected to the pressurizing gas in the drain pot 10, a storage container 17 connected to the outlet side of the compressor 12, and a constant amount feeder 8 for the pulverized coal bottle 5. Pulverized coal carrier pipeline 23 via
, A lock hopper 14 connected to the pulverized coal outlet side of the receiver hopper 13 via a valve, and a supply hopper connected to the pulverized coal outlet side of the lock hopper 14 via a valve. 15, a pulverized coal supply line 24 that connects the pulverized coal outlet side of the supply hopper 15 and the pressure reactor 16 via the constant amount feeder 8, the outlet of the storage container 17 and the heat exchanger 18 The heating gas inlet side communicates with each other, and further the heated gas outlet side of the heat exchanger 18 communicates with the lock hopper 14 and the supply hopper 15 through a valve, and a sealing pipeline 21 and the bag filter 6,
The heating gas side of the heat exchanger 18, the cooled gas side of the cooler 9, the drain pot 10, the blower 11, and the recycle pipe line 19 for connecting the hot air pipe line 22 in this order are included. The recycle line 19 also connects the outlet of the blower 11 and the pulverized coal transfer line 23 on the outlet side of the constant quantity feeder 8.

The lock hopper 14 and the supply hopper 15 are pulverized coal storage means for pressurized supply of pulverized coal.

The operation of the apparatus having the above configuration will be described below. A fixed amount of coal stored in the coal hopper 1 is supplied to the mill 3 by the coal feeder 2 and pulverized and pulverized. High-temperature combustion gas is generated in the combustion furnace 4. The oxygen content in this combustion gas is about 1 to 2%. Further, the temperature of this combustion gas is usually 1000 ° C, and if this high temperature combustion gas is directly supplied to the mill 3, there is a risk of carbonization and ignition of coal. Therefore, the combustion gas generated in the combustion furnace 4 is mixed with the cooled and dehydrated combustion gas sent from the blower 11 through the recycle pipe 19, and is subjected to the carbonization of coal and the temperature below the ignition temperature to the mill 3. Sent in. The combustion gas sent to the mill 3 dries and conveys 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 set to about 200 to 250 ° C. Moreover, since the water content is low, the drying efficiency in the mill 3 is good.

The dried pulverized coal is sent to the pulverized coal bottle 5 together with the introduced combustion gas for temporary storage. The temperature of this dry pulverized coal is about 80 to 90 ° C, but since it is dry, it is prone to spontaneous combustion in an air atmosphere. The combustion gas sent to the pulverized coal bottle 5 is taken out through the bag filter 6, and a part of the combustion gas is used as a recycled gas in the heat exchanger.
After being cooled by the cooler 9 through the heating fluid side of 18, it is introduced into the drain pot 10. The recycled gas introduced into the drain pot 10 is dehydrated, then pressurized by the blower 11, and part of the recycled gas is supplied to the lower taper 7 of the pulverized coal bottle 5 through the aeration pipe 20. The recycled gas supplied to the lower taper portion 7 makes the pulverized coal bottle 5 an inert atmosphere and suppresses the occurrence of spontaneous combustion.

The lower tape part 7 to which recycled gas is supplied is
A double structure having an outer wall is formed, the double structure portion is divided into a plurality of sections, and the inner wall is provided with a plurality of openings for each section. The outer wall is provided with at least one gas blowing port for each section. Recycled gas is sequentially supplied to each of the compartments from the gas injection port of the outer wall, and is ejected into the pulverized coal bottle 5 through the opening provided in the inner wall to prevent the formation of bridges in the pulverized coal bottle 5. Care is taken so that the amount of gas is not reduced.

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 duct 22, and the combustion gas temperature is lowered as described above. , The mill 3 is supplied to dry the pulverized coal in the mill.

The pulverized coal in the pulverized coal bottle 5 is conveyed to the receiving hopper 13 by a part of the recycle gas pressurized by the blower 11 after the fixed amount 8 is supplied. The pulverized coal in the receiving hopper 13 is sent to the supply hopper 15 via the lock hopper 14, and then is supplied to the pressure reactor 16 via the constant quantity feeder 8.

A part of the recycled gas dehydrated in the drain pot 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
If necessary, it is sent to the heat exchanger 18 via the aeration pipe 21, heated and heated, and then sent to the lock hopper 14 and the supply hopper 15 as a sealing gas to pressurize each hopper and form a bridge. To prevent.

According to this example, the combustion gas generated in the combustion furnace is
Drying of pulverized coal in mill 3, pulverized coal bottle 5 from mill 3
The pulverized coal is conveyed to the pulverized coal, and the combustion gas after the conveyance is recovered from the pulverized coal bottle 5, cooled and dehydrated, and then used as a recycled gas to prevent bridging of the pulverized coal bottle 5. The amount of active gas used can be reduced. According to the present embodiment, the recycled gas is further used to cool the high-temperature combustion gas sent from the combustion furnace, pressurize the lock hopper and the supply hopper, seal, prevent the formation of bridges, and pulverized coal from the pulverized coal bin 5 to the receiving hopper. Since it is also used for the transportation of coal, the amount of inert gas used can be reduced, and an economical pulverized coal supply device can be obtained.

In addition, although the combustion furnace for the pulverized coal supply device has been described in the present embodiment, it is natural that the combustion furnace dedicated to the pulverized coal supply device need not be provided as long as there is a usable combustion device.

〔The invention's effect〕

According to the present invention, the amount of the inert gas such as nitrogen used is reduced, and it is possible to reduce the cost of the facility for producing the inert gas such as nitrogen and the recycling facility.

[Brief description 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 a conventional technique. 3 ... Crushing and drying means (mill), 4 ... Combustion furnace, 5
... Pulverized coal storage means (pulverized coal bottle), 9 ... Cooling means (cooler), 10 ... Dehydration means (drain pot), 11 ...
1st pressurizing means (blower), 12 ... 2nd pressurizing means (compressor), 14, 15 ... Pulverized coal storage means (lock hopper, supply hopper) for supplying under pressure, 17 ... Storage Container, 18 ... Heat exchanger, 19 ... Recycling pipeline, 20 ... Aeration pipeline, 21 ... Sealing pipeline, 22 ... Hot air pipeline, 23 ... Pulverized coal transport pipeline.

Claims (6)

(57) [Claims] 1. A pulverizing means for pulverizing coal into pulverized coal, a drying means for drying the pulverized coal with hot air, a combustion gas which is used as hot air, and a hot air pipe line is passed to the drying means. A combustion furnace for supplying, a pulverized coal storage means for storing the dried pulverized coal conveyed to the combustion gas after pulverized coal drying, a cooling means for cooling the combustion gas passing through the pulverized coal storage means, and a cooled A dehydrating means for dehydrating the combustion gas, and a first pressurizing means for pressurizing the cooled and dehydrated combustion gas,
A pulverized coal supply device including an outlet of the first pressurizing means and an air lacing line communicating the lower portion of 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 duct are communicated with each other. 3. A pulverized coal storage means comprising a plurality of pulverized coal storage means for pressure supply, which are sequentially connected to the pulverized coal storage means through a pulverized coal transporting line, and a first pressing means outlet and the above The pulverized coal supply device according to claim 1 or 2, wherein the pulverized coal transporting line is communicated with the pulverized coal transporting line. 4. A seal for connecting, through a valve, a second pressurizing means connected to the dehydrating means, an outlet of the second pressurizing means and a pulverized coal storage means for pressurizing supply. The pulverized coal supply device according to any one of claims 1 to 3, further comprising a pipe line for use. 5. A heat exchanger and / or a storage container 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 in the sealing pipeline. The pulverized coal supply device according to claim 4, wherein the pulverized coal supply device is provided. 6. A container for storing pulverized coal, wherein an outer wall of the lower part of the container is formed into a double wall, and the inside of the double wall is divided into a plurality of compartments, and the inner wall of the double wall is formed. Is a pulverized coal storage container in which a plurality of openings are provided in each of the compartments and at least one gas blowing port is provided in the outer wall of each compartment.