KR20120075167A - Device and method for drying coal for coke oven - Google Patents

Abstract

PURPOSE: A coal drying apparatus for coke and a drying method are provided to prevent the agglomeration of coal by changing operating conditions according to the content of humidity in coal. CONSTITUTION: A coal drying apparatus for coke comprises a fluidized bed dryers(10, 11), a coal supplying unit(20), hot air supplying units(30, 31), and a circulation unit. The fluidized bed dryers dry coal through fluidization. The coal supplying unit and hot air supplying units are connected to the fluidized bed dryers and pours coal to a spreader plate. The hot air supplying units supply hot air to the spreader plate. The circulation unit circulates coal by changing the flow velocity of the hot air.

Description

Coal Drying Apparatus and Drying Method for Coke {DEVICE AND METHOD FOR DRYING COAL FOR COKE OVEN}

The present invention relates to a technique for drying coal charged into a coke oven for coke production. More specifically, the present invention relates to a coal drying apparatus and method for coke, which can increase the drying efficiency.

The rapid increase in global crude steel production is increasing the demand for coal for iron ore and metallurgical coke production. As a result, the price of coal and exhaustion of high-quality coking coal are becoming increasingly difficult. Under these circumstances, various technologies have been developed and applied to diversify the coal used for the manufacture of metallurgical coke and increase the use cost of coking coal having a weak coking force.

As a pre-treatment technology of the double coal, a drying technique for reducing the moisture of the coal charged into the coke oven is mainly used. The fluidized bed dryer which is excellent in drying efficiency is mainly used for the moisture drying of coal. In the fluidized bed dryer, coal is dried by fluidization by hot air.

Conventional fluid bed dryers for coal drying have a narrow and long structure arranged horizontally. Hot air for drying coal is supplied from the bottom of the fluidized bed dryer. The coal is injected into one end of the fluidized bed dryer is moved in the horizontal direction is dried through the fluidization process. The dried coal is discharged from the other end of the fluidized bed dryer, and the pulverized coal generated in the coal drying process is classified from the dried coal and discharged to the upper part. The classified pulverized coal is formed into a certain shape in a molding facility. The shaped pulverized coal is mixed with the granulated coal dried in a fluidized bed dryer and then fed into the coke oven to make coke.

However, since the hot air is dispersed and poured along the fluidized bed dryer, the conventional structure has a problem in that the fluidized bed of coal is not properly formed at the supply position of the fluidized bed dryer when high moisture coal containing a lot of water is introduced into the fluidized bed dryer. . Therefore, the drying operation by the fluidization of coal is not smoothly made.

In addition, the conventional structure described above is poor in the classification efficiency because the drying and classification of coal in a fluidized bed dryer. In particular, there is a problem in that the pulverized coal classification efficiency is not good because the pulverized coal is classified intensively at the point where the dried coal is discharged.

In addition, the above-described conventional structure is because the hot air of the same temperature is supplied to both the coal discharge position from the coal supply position of the fluidized bed dryer, the coal drying efficiency and energy efficiency is reduced. That is, at a supply position where coal is supplied into the fluidized bed dryer, low temperature and high moisture coal and hot air come into contact with each other. At the coal discharge position of the fluidized bed dryer, the dried and elevated temperature coal comes into contact with hot air of the same temperature. Such a conventional structure has no efficient distribution of hot air, and the drying efficiency of coal is of course reduced, as well as a waste of energy.

Accordingly, the present invention provides a coal drying apparatus and method for coke, which is capable of increasing flow efficiency for high moisture coal.

In addition, the present invention provides a coal drying apparatus and method for coke that can increase the drying efficiency of coal.

To this end, the drying apparatus includes a fluidized bed dryer for fluidizing and drying coal by hot air emitted through a dispersion plate installed therein, a coal supply unit connected to the fluidized bed dryer to inject coal onto the dispersion plate, and a fluidized bed dryer. It may be connected to the hot air supply unit for supplying hot air to the dispersion plate, the flow rate of the hot air blown through the dispersion plate of the fluidized bed dryer may include a circulation unit for circulating the coal so as to be different from the central portion and the peripheral portion of the dispersion plate, respectively. .

The apparatus may have a structure in which at least two fluidized bed dryers are provided and sequentially connected to each other so that coal is dried by passing through each fluidized bed dryer in turn.

The circulation unit may be installed in the foremost fluidized bed dryer among the fluidized bed dryers sequentially connected.

The circulation unit is provided in a lower chamber formed under the distribution plate of the fluidized bed dryer, and includes a separation tube for partitioning the lower chamber to independently supply hot air to the central portion and the peripheral portion of the distribution plate. The central hot air line includes a central hot air line connected to supply hot air to the center of the distribution plate through the inside of the separation pipe and an ambient hot air line connected to the lower chamber to supply hot air to the periphery of the distribution plate through the outside of the separation pipe. The surrounding hot air line may have a structure for supplying hot air of different flow rates.

The circulation part may have a structure in which the flow rate of the hot wind supplied to the center of the distribution plate is greater than the flow rate of the hot wind supplied to the peripheral portion.

The flow rate of the hot air supplied to the center of the dispersion plate may be a structure 5 to 8 times larger than the minimum fluidization rate of coal.

The flow rate of hot air supplied to the periphery of the dispersion plate may have a structure 1 to 2 times larger than the minimum fluidization speed of coal.

The circulation unit may further include a circular tube spaced apart from the distribution plate in the upper portion of the central portion of the distribution plate in the fluidized bed dryer.

The circular tube may be made of 1/2 ~ 1/4 size of the inner diameter of the fluidized bed dryer.

The separation tube may be formed in a size corresponding to the circular tube.

On the other hand, in the drying method of supplying hot air into the fluidized bed dryer to fluidize and dry coal, the flow rate of the hot air supplied to the central portion of the dispersion plate of the fluidized bed dryer and the flow rate of the hot air supplied to the periphery of the dispersion plate, respectively It may have a different structure to circulate and dry coal.

This drying method may be sequentially dried by feeding the first dried coal to the next fluidized bed dryer through a multi-stage fluidized bed dryer.

The drying method may have a structure in which the flow rate of the hot air supplied to the central portion of the dispersion plate is greater than the flow rate of the hot air supplied to the peripheral portion.

In the drying method, the flow rate of the hot air supplied to the center of the dispersion plate may be 5 to 8 times larger than the flow rate of the hot air supplied to the peripheral part.

As described above, according to this embodiment, the drying efficiency can be improved by constructing the fluidized bed in multiple stages and drying the coal.

In addition, by varying the operating conditions according to the moisture content of the coal, it is possible to prevent coal from agglomeration in the inside, even in the case of high moisture coal can increase the flow efficiency.

As such, the coal drying efficiency can be increased to increase the loading density of coal charged into the coke oven, thereby improving the coke quality.

In addition, the use of low-cost low-cost coal can be significantly improved, and the coke oven operation can be stably maintained.

1 is a schematic diagram illustrating a coal drying facility according to the present embodiment.
2 is a sectional view taken along the line AA of FIG. 1 as a coal drying equipment according to the present embodiment.
3 is a schematic view for explaining the operation of the coal drying equipment according to the present embodiment.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As can be easily understood by those skilled in the art, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Where possible the same or similar parts are represented with the same reference numerals in the drawings.

All terms including technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, this Example is demonstrated based on the Example applied to drying coke oven coal. However, the present invention is not limited thereto, and is applicable to drying of various raw materials including coal of various applications.

1 shows a coal drying plant according to this embodiment.

As shown, the apparatus includes a fluidized bed dryer (10, 11), coal supply unit 20 and hot air supply unit (30, 31). In addition, the apparatus further includes a coal briquette maker 60 for agglomeration of finely divided coal particles (hereinafter referred to as pulverized coal) generated in the coal drying process.

The coal supplier 20 is connected to the fluidized bed dryer 10 to inject coal onto the dispersion plate 12. The hot air supply units 30 and 31 are connected to the lower portion of the fluidized bed dryers 10 and 11 to supply hot air to the dispersion plates 12 of the respective fluidized bed dryers.

In addition, the fluidized bed dryers 10 and 11 fluidize and dry coal by hot air emitted through the dispersion plate 12 installed therein.

In the present embodiment, two fluidized bed dryers 10 and 11 are provided, and two fluidized bed dryers are connected in multiple stages. For convenience of explanation, the fluidized bed dryer in the front according to the coal movement order is called the first fluidized bed dryer 10, and the rear fluidized bed dryer connected to the first fluidized bed dryer is called the second fluidized bed dryer 11.

In the present embodiment, the first fluidized bed dryer 10 and the second fluidized bed dryer 11 are sequentially disposed, and the inlet port 17 of the outlet 18 of the first fluidized bed dryer 10 and the second fluidized bed dryer 11 are provided. The connecting pipe 19 for moving coal is provided in between.

The first fluidized-bed dryer 10 is arranged in a vertical shape and a distribution plate 12 for ejecting hot air to the top is installed at the bottom. The lower chamber 14 is connected to the hot air supply unit 30 to introduce a hot air into the lower portion of the distribution plate 12. And the main tower 16 is dried vertically above the dispersion plate 12 is made. The main tower 16 is provided with an inlet 17 through which coal is introduced and an outlet 18 through which coal dried in the fluidized bed is discharged. In addition, a cyclone 50 for collecting pulverized coal generated in the coal drying process is connected to an upper portion of the main tower 16. The fluidized bed dryer (10, 11) is a heat insulating material is installed on the outer surface to prevent heat loss, the thermocouple is provided with a pressure sensor for detecting the temperature and pressure in the fluidized bed.

The second fluidized bed dryer 11 has the same structure as that of the first fluidized bed dryer 10 described above. The same reference numerals are used for the same configuration, and detailed description thereof will be omitted below. The second fluidized bed dryer 11 is also connected to the hot air supplier 31 to fluidize and dry coal with hot air supplied. In the present embodiment, the hot air supply units 30 and 31 are separately provided in the first fluidized bed dryer and the second fluidized bed dryer, respectively, to separately supply the hot air to each fluidized bed dryer.

The coal supply unit 20 quantitatively transfers the coal loaded in the hopper 22 through a screw feeder 24 at the bottom of the hopper 22 to the inside of the main column 16 of the first fluidized bed dryer 10. It is structure to supply. The chute 26 connected to the coal inlet 17 of the main column 16 is installed at the screw feeder 24 exiting side. The coal transported by the screw feeder 24 is introduced into the main column 16 through the chute 26. The coal supply unit 20 may be further installed inside the hopper 22 for smooth flow of coal.

In the present embodiment, since the second fluidized bed dryer 11 receives the coal dried through the fluidization process in the first fluidized bed dryer 10 through the connection pipe 19, a separate coal supply unit is unnecessary.

The hot air supply unit 30 is installed in a hot air line 32 connected to the lower chamber 14 of the first fluidized bed dryer 10 and a blower 34 for supplying hot air, and installed on the hot air line 32. And a heater 36 for heating the hot air to be supplied. In addition, the flow meter 38 for adjusting the flow rate of the hot air supplied to the hot air line 32 is installed. The hot air may be air heated by the heater 36 or hot gas generated in a steel mill, for example, exhaust gas discharged from a combustion chamber of a coke oven, and is not particularly limited. In the case of using the exhaust gas discharged from the combustion chamber of the coke oven as hot air, the heater may not be included in the hot air supply because the hot air does not need to be heated.

The hot air supply unit 31 connected to the second fluidized bed dryer 11 to supply hot air to the second fluidized bed dryer also has the same structure as the hot air supply unit 30 connected to the first fluidized bed dryer 10. Therefore, the same reference numerals are used for the same components as the hot air supply unit 30, and detailed descriptions thereof will be omitted.

Here, the apparatus has a structure having two multi-stage fluidized bed dryers as described above, and coal is sequentially dried and classified while passing through two fluidized bed dryers. Hereinafter, classification means separating pulverized coal from undried coal.

With the above structure, the coal supplied to the first fluidized bed dryer 10 by the coal supply unit 20 is first fluidized by hot air in the first fluidized bed dryer 10 and undergoes a drying process. Hot air is introduced into the lower chamber 14 of the fluidized bed dryer by the blower 34. The hot gas introduced into the lower chamber 14 is ejected to the upper part through the distribution plate 12 installed on the upper part of the lower chamber 14. Hot air blown upward through the dispersion plate 12 forms an upward flow. This upward flow forms a fluidized bed on the dispersion plate 12. Coal flows in this fluidized bed and drying occurs by hot air.

Coal dried in the fluidized bed of the first fluidized bed dryer 10 and scattered above the fluidized bed is discharged through the outlet 18 of the first fluidized bed dryer 10. Coal discharged from the first fluidized bed dryer 10 is introduced into the second fluidized bed dryer 11 through a connection pipe 19 connected to the outlet 18 of the first fluidized bed dryer 10.

The coal introduced into the second fluidized bed dryer 11 is secondarily dried while being fluidized by hot air on the dispersion plate 12 of the second fluidized bed dryer 11. Coal dried in the second fluidized bed dryer 11 and scattered above the fluidized bed is discharged to the outside through an outlet 18 of the second fluidized bed dryer 11. The fine powder generated in the first fluidized bed dryer 10 and the second fluidized bed dryer 11 is classified in each dryer 10 and collected through the cyclone 50 and the bag filter 52 connected to the upper part.

As such, by drying the coal in multiple stages through two separate fluidized bed dryers, the operating conditions of each fluidized bed dryer can be adjusted to increase the efficiency of coal drying and pulverized coal.

On the other hand, the apparatus circulates the coal in the upper portion of the dispersion plate 12 by varying the flow rate of the hot air blown out through the dispersion plate 12 of the fluidized bed dryer 10 to the central portion and the peripheral portion of the dispersion plate 12, respectively. It includes a circulation for. Here, the central portion means a central portion including the center of the dispersion plate 12, and the periphery means a central portion outer portion.

The circulation section can be installed in both fluidized bed dryers. In this embodiment, the circulation unit is installed in the first fluidized bed dryer 10 disposed in front of the two fluidized bed dryers arranged in multiple stages.

The circulation portion is provided with a separation tube 40 for partitioning the lower chamber 14 to independently supply the hot air to the central portion and the peripheral portion of the distribution plate 12 in the lower chamber 14, the hot air supply unit 30 In the separation pipe 40 is configured to supply hot air of different flow rates into the inside and outside, respectively.

The hot air line 32 for supplying hot air from the hot air supply unit 30 to the lower chamber 14 is divided into two and connected to the separation pipe 40 and the lower chamber 14, respectively. Here, the hot air line connected to the separator tube 40 among the hot air lines 32 is referred to as a central hot air line 33, and the hot air line connected to the lower chamber 14 is referred to as a peripheral hot air line 35.

The hot air supply unit 30 supplies hot air of different flow rates to the central hot air line 33 and the peripheral hot air line 35, respectively. In the present embodiment, the hot air supply unit 30 supplies the hot air with a flow rate of hot air supplied to the central portion of the distribution plate 12 larger than that of the hot air supplied to the peripheral portion. The flow rate of hot air is controlled through the flow meter 38 of the hot air supply unit 30. Hot air is supplied at a set flow rate through the flow meter 38 installed in each hot air line 32.

Accordingly, hot winds of different speeds are ejected to the central portion and the peripheral portion of the dispersion plate 12 so that coal rises at the central portion of the dispersion plate 12 and descends and circulates at the peripheral portion.

Here, the flow rate of the hot air supplied to the central portion of the distribution plate 12 may have a structure 5 to 8 times larger than the minimum fluidization speed of coal. In addition, the flow rate of the hot air supplied to the periphery of the dispersion plate 12 may be a structure 1 to 2 times larger than the minimum fluidization speed of coal. The minimum fluidization rate is approximately 0.12 m / sec at the minimum rate for flowing coal particles. In the following description, the minimum fluidization speed is expressed as 1 Qmf and is approximately 0.12 m / sec, so that 5 times the minimum fluidization speed is defined as 0.6 m / sec and 8 times 1.0 m / sec.

If the flow rate of the hot air supplied to the central portion of the distribution plate 12 is lower than the speed does not raise the coal sufficiently, the coal circulation is not properly made. When the flow rate of the hot air supplied to the center portion of the dispersion plate exceeds the above range, the power for the hot air supply is increased to increase the operating cost.

In addition, if the flow rate of the hot air supplied to the peripheral portion of the dispersion plate 12 exceeds the above range, the speed difference with the flow rate of the hot air supplied to the center of the dispersion plate is small, the coal circulation is not active actively, so the coal is below the periphery. The phenomenon of falling back occurs.

The apparatus has a structure in which a circular pipe 42 is further installed in the main column 16 of the fluidized bed dryer 10 so that the circulation flow can be more reliably formed on the upper part of the distribution plate 12. The circular pipe 42 is a circular tubular structure disposed vertically along the longitudinal direction of the main tower 16 in the main tower 16, and is spaced apart from the distribution plate 12 on the central portion of the distribution plate 12. .

Accordingly, the fluidized bed formed on the distribution plate 12 by the circular tube 42 is reliably partitioned into two regions, namely, a central portion and a peripheral portion thereof. This makes it possible to reliably form a circulating flow of coal rising inside the circular pipe 42 and descending from the outside.

As shown in FIG. 2, the circular pipe 42 is disposed at the center of the main tower 16, and is fixed to the inner circumferential surface of the main tower 16 via the support member 44 in a state spaced apart from the distribution plate 12. Is installed.

In this embodiment, the circular tube 42 is made of 1/2 ~ 1/4 size of the inner diameter of the fluidized bed dryer (10). The separation tube 40 may also be formed in a size corresponding to the circular tube 42. If the inner diameter of the circular tube is smaller than the above range, the inner diameter of the circular tube is so small that hot air supplied to the center portion may leak out of the circular tube. In addition, when the inner diameter of the circular tube is larger than the above range, there is a fear that the coal having risen beyond the inner diameter of the circular tube may fall through the inside of the circular tube again. The circulation of coal is not made properly.

Referring to Figure 3 describes the operation of the device as follows.

By this apparatus, hot wind of different flow rates is supplied through the central hot air line 33 and the surrounding hot air line 35, respectively.

The hot air supplied to the central hot air line 33 is connected to the separation pipe 40 and is supplied into the separation pipe 40. The separation pipe 40 is connected to the central portion of the distribution plate 12, so that the hot air introduced into the separation pipe 40 is ejected to the central portion of the distribution plate 12. Accordingly, hot air having a relatively high flow rate is ejected to the central portion of the dispersion plate 12.

The hot air supplied to the peripheral hot air line 35 is connected to the lower chamber 14 and is supplied between the outside of the separation pipe 40 and the lower chamber 14. Since the separation pipe 40 and the lower chamber 14 are connected to the periphery of the distribution plate 12, hot air introduced into the area is ejected through the periphery of the distribution plate 12. Accordingly, a relatively slow flow of hot air is blown out to the periphery of the dispersion plate 12.

As such, relatively high velocity hot air is blown out to the central portion of the dispersion plate 12, and relatively low velocity hot air is blown out to the periphery of the dispersion plate 12. Therefore, a circulating flow from the central portion of the distribution plate 12 to the peripheral portion occurs. Along this flow, coal rises in the center of the dispersion plate 12. The rising coal is lifted up through the interior of the circular tube 42 disposed above the dispersion plate 12. And when the upward force is weakened past the upper portion of the circular tube 42 is pushed to the outside of the circular tube 42, that is, descending through the periphery of the dispersion plate 12, that is, the flow rate is relatively slow.

As shown therein a circular flow is formed along the inside of the circular pipe 42 and descends between the circular pipe 42 and the inner surface of the main tower 16, the coal is a circular pipe ( 42).

Therefore, when coal containing excess moisture is introduced into the fluidized bed dryer 10, coal is attached to the dispersion plate 12 in the past, so that it is difficult to fluidize. However, in the present apparatus, coal is dispersed at a central portion due to the high flow rate. It rises up from to the circulating flow that descends from the periphery. By this circulation flow, the coal can continue to go through the process of drying while descending to the outside of the circular tube 42 and ascending inside the circular tube 42. Accordingly, even in the case of high moisture coal, it is possible to increase the drying efficiency by allowing the coal to circulate in the fluidized bed.

While the illustrative embodiments of the present invention have been shown and described, various modifications and alternative embodiments may be made by those skilled in the art. Such variations and other embodiments will be considered and included in the appended claims, all without departing from the true spirit and scope of the invention.

10 first fluid bed dryer 11 second fluid bed dryer
12: dispersion plate 14: air chamber
16: pylon 17: slot
18: outlet 19: connector
20: coal supply unit 30,31: hot air supply unit
33: central hot air line 35: surrounding hot air line
40: separating pipe 42: round pipe

Claims (15)

A fluidized bed dryer for fluidizing and drying coal by hot air emitted through a dispersion plate installed therein;
A coal supply unit connected to the fluidized bed dryer to inject coal onto a dispersion plate,
Hot air supply unit connected to the fluidized bed dryer for supplying hot air to the dispersion plate,
The circulation part for circulating coal by making the flow velocity of the hot air blown out through the dispersion plate of the said fluidized bed dryer different from a center part and a peripheral part of a dispersion plate, respectively.
Coal drying apparatus for coke comprising a. The method of claim 1,
At least two fluidized bed dryers are provided and connected sequentially, coal drying apparatus for coke having a structure in which coal is dried by passing through each fluidized bed dryer in turn. The method of claim 2,
The circulation unit is a coal drying apparatus for the coke is installed in the fluidized-bed dryer in the front of each fluidized bed dryer sequentially connected. The method according to any one of claims 1 to 3,
The circulation unit is a coke coal drying apparatus having a structure in which the flow rate of the hot air supplied to the central portion of the distribution plate is larger than the flow rate of the hot air supplied to the peripheral portion. The method of claim 4, wherein
The flow rate of hot air supplied to the center of the distribution plate is a coal drying apparatus for coke having a structure of 5 to 8 times larger than the minimum fluidization rate of coal. The method of claim 5, wherein
The flow rate of hot air supplied to the periphery of the dispersion plate is a coal drying apparatus for coke having a structure 1 to 2 times larger than the minimum fluidization rate of coal. The method of claim 4, wherein
The circulation unit is provided in a lower chamber formed in the lower portion of the distribution plate of the fluidized bed dryer, and includes a separation pipe partitioning the lower chamber to independently supply hot air to the central portion and the peripheral portion of the distribution plate,
The hot air supply unit is connected to the separation pipe and the central hot air line for supplying hot air to the center of the distribution plate through the inside of the separation pipe and the peripheral hot air line connected to the lower chamber to supply hot air to the periphery of the distribution plate through the outside of the separation pipe. Including, the coke coal drying apparatus having a structure for supplying hot air of different flow rates to the central hot air line and the surrounding hot air line, respectively. The method of claim 7, wherein
The circulation unit further comprises a circular pipe spaced apart from the dispersion plate in the upper portion of the central portion of the distribution plate in the fluidized bed dryer for the coke coal drying apparatus. The method of claim 8,
The separation pipe is a coal drying apparatus for coke made of a size corresponding to the circular pipe. The method of claim 8,
The circular pipe is a coal drying apparatus for coke having a size of 1/2 ~ 1/4 of the inner diameter of the fluidized bed dryer. In the coal drying method of supplying hot air into the fluidized bed dryer to fluidize and dry coal,
A coal drying method for coke, wherein coal is circulated and dried by varying a flow rate of hot air supplied to a central portion of a dispersion plate of a fluidized bed dryer and a flow rate of hot air supplied to a peripheral portion of a dispersion plate. The method of claim 11,
Coal drying method for coke to sequentially dry coal through a multi-stage fluidized bed dryer. The method according to claim 11 or 12,
A method of drying coal for coke, wherein a flow rate of hot air supplied to the central portion of the dispersion plate is greater than a flow rate of hot air supplied to a peripheral portion. The method of claim 13,
The flow rate of hot air supplied to the center of the dispersion plate is 5 to 8 times larger than the minimum fluidization rate of coal coal drying method for coke. 15. The method of claim 14,
The flow rate of hot air supplied to the periphery of the dispersion plate is 1 to 2 times larger than the minimum fluidization rate of coal coal drying method for coke.

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