JPS62124189A - Coal dryer - Google Patents

Abstract

PURPOSE:A dryer capable of providing stable, high drying efficiency, by setting a centrifugal dehydrator in the upper steam side of a coal crusher and an upright coal dryer in the downstream side of the coal crusher and a blender. CONSTITUTION:For example, coal for coke, having >=80wt% particles with <=0.3mm particle size is dehydrated by a centrifugal dehydrator 6 into <=9wt% water content of coal and sent through a crusher 13 to a blender 14 separately corresponding to grade. The blended coal is fed to an upright coal dryer 15, dried to a given water content and sent to a coal tank 16 at the top of coke oven. EFFECT:Since fluctuation of water content of coal to be dried is small, a heat generating device for feeding heat to a dryer can be extremely miniaturized.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an apparatus for drying coal for coke production.

(Prior Art) The moisture content of coking coal fluctuates from about 6 to 13 inches depending on rainfall. After drying the coal to a fixed moisture content of about 5% or 0%, charging it into a coke oven shortens the carbonization time of the coal and improves the productivity of the coke oven. It is well known that it has the effect of increasing the overall strength of the body.

For this reason, there are examples of conventional flash dryers and fluidized bed dryers being incorporated into coke oven equipment and operating as actual equipment.

Furthermore, as an efficient coal dryer, there is a vertical dryer as shown in FIG. 2 (Japanese Patent Application No. 188221/1982).

This dryer is a vertical dryer in which a plurality of heating tubes with an A-shaped cross section are arranged in the tank, a metal heat medium passage is formed inside the heating tubes, and a space under the heating tubes is used as an air passage for discharging water vapor. . Coal is supplied into the tank 17 by a belt conveyor 23.

The coal is heated by the heat transfer tube 18 while moving up and down in the tank,
The water vapor is removed by the carrier gas and dried.
It is discharged to the outside of the tank by the discharge device 29.

A heat medium such as steam passes through the inside 19 of the A-shaped heat exchanger tube, and a carrier gas passage is formed in the lower part 20 of the heat exchanger tube. In the carrier gas passage 20, a ventilation passage and an exhaust passage are arranged for each stage of heat exchanger tubes. The tank is divided into several blocks, and each block is vibrated by a vibration generator 22 to facilitate the descent of the coal. The space between each block is sealed with a cloth cover 27 to prevent coal from flowing out. Each block is connected to a frame 26 by a spring 21 so that it can easily vibrate.

In the figure, 24 is a heat medium supply pipe, 25 is a carrier gas supply pipe, 2
8 indicates a block casing.

(Problems to be Solved by the Invention) In the above-mentioned vertical dryer, the particle size of the coal is 3! When drying coal for coke production that has 80% or more of OL or less, or 20% or more of 0.3am or less, if the moisture content of the coal is 9% or more, the coal has great adhesion resistance and stickiness. Therefore, if the heat transfer tube is stationary, the coal will not descend smoothly. Therefore, in order to smoothly lower the material and perform drying efficiently, it is necessary to install a mechanism that vibrates or rocks the heat exchanger tube. However, vibrating or rocking the heat exchanger tubes complicates the equipment, making it difficult to design equipment with a large drying capacity, and furthermore, has the drawback of increasing operating costs such as electricity costs. have. In addition, even if such a vibration device is installed,
When the moisture content is high, the material falls unevenly and a decrease in drying efficiency is inevitable.

(Means and actions for solving all problems) Generally, in the case of coking coal with a particle size of 80% or less of 3raR or less, the adhesion resistance and stickiness of the coal increase as the moisture content increases. When the moisture content exceeds 9%, they increase significantly, and when the moisture content exceeds 14%, the tackiness tends to decrease.

The present invention was made in order to maintain stable and high drying efficiency of a vertical coal dryer, and in coke manufacturing coal processing equipment, a centrifugal dehydrator is installed upstream of a coal crusher,
This coal drying apparatus is characterized in that a vertical coal dryer is provided downstream of a coal crusher and blending equipment.

After dehydrating the coal to less than 9 cm using a centrifugal dehydrator, the coal is fed to a vertical coal dryer and dried to a predetermined moisture content. Besides, the fall of coal in vertical drying is uniform.
Stable and highly efficient drying efficiency can be obtained.

In addition, several to dozens of fine particles of coal create pseudo particles using moisture as a medium. Water in pseudo particles is difficult to dehydrate using a centrifugal dehydrator. For example, if the amount of coal particles of 0.5w or less is large, the dehydration rate will be poor. Since dehydration using a centrifugal dehydrator is more effective when there are fewer particles of 0.5 m or less, it is appropriate to install the dehydrator upstream of the coal crusher and dehydrate coal with a water content of 8% or more.

(Embodiment) FIG. 1 shows an embodiment of the present invention. Coal discharged from a coal yard by a flamer or the like is supplied to a surge hopper 2 by a belt conveyor 1.

A certain amount of coal is cut out by a certain amount cutting device at the bottom of the surge hole. Continuous moisture analyzer 4 measures the moisture content of this coal.
Quantitate by There is a reversible conveyor 3 downstream of the quantitative cutting device, and when the coal moisture content is 8% or less, the coal is sent to the crusher 13.

If the coal moisture is 8% or more, the coal will vibrate at 25+ m]
: Sent to City 5 and sieved. Then, the portion above 25 m is directly sent to the crusher 13. 25m below is a centrifugal dehydrator 6 and then a belt conveyor 10, . 11 Yoshi, crusher 13
sent to. Since the water discharged from the centrifugal dehydrator 6 contains fine coal particles, the fine coal particles are settled in a settling tank 8.

The precipitated slurry is sent to a centrifuge 7 by a pump 9, and the pulverized coal cake is recovered, and sent to a crusher 13 together with the dehydrated coal by a belt conveyor 10.11. The coal discharged from the crusher 13 is sent to a blending tank 14 according to brand.

Each brand of coal is blended in a predetermined ratio by a quantitative cutting device below the blending tank 14. The blended coal is supplied to a vertical coal dryer 15, and after drying the coal to a predetermined moisture content, the coal is sent to a charging coal tank 16 at the top of the coke oven. Incidentally, the F liquid discharged from the settling tank and the centrifugal separator is put into the yard drainage ditch, and is discharged after being treated together with the coal yard drainage.

(Effects of the Invention) By treating coal with a moisture content of 8% or more with a dehydrator, it is possible to always keep the coal moisture supplied to the vertical dryer at 9% or less. If the moisture content is less than 9%, there is no need for special equipment such as vibration in the vertical dryer to promote coal fall, and by setting the gaps between the heat transfer tubes within an appropriate range, the material will dry smoothly. descend to

In this way, by reducing the water content to 9% or less using a centrifugal dehydrator, the fluidity of coal in the heat exchanger tube section can be improved not only in vertical dryers but also in steam indirect heating rotary dryers, etc. 9, drying efficiency is improved.

Furthermore, since there is little variation in the moisture content of the coal supplied to the dryer, it is possible to significantly downsize the heat generating equipment that supplies heat to the dryer.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a coal drying apparatus according to an embodiment of the present invention, showing a distance 70- from a coking coal yard to a charging coal tank. FIG. 2 is a diagram showing an example of an indirect heating type coal dryer. 1: Belt conveyor, 2: Surge hopper, 3:
Reversible conveyor, 4: Continuous moisture analyzer, 5:
Vibration sieve, 6: Centrifugal dehydrator, 7: Centrifugal separator, 8: Sedimentation tank, 9: Pump, 10.11: Belt conveyor. 13: Pulverizer, 14: Blending tank, 15: Vertical coal dryer, 16: Charging coal tank.

Claims (1)

[Claims] Coal processing equipment for coke production is characterized in that a centrifugal dehydrator is provided upstream of a coal pulverizer, and a vertical coal dryer is provided downstream of the coal pulverizer and blending equipment. drying equipment.