JPS633090A - Drying of feedstock coal for coke - Google Patents

Abstract

PURPOSE:To provide the titled drying process so as to enable electric power to be saved by drying in advance, feedstock coal to a specified water content followed by storage in a blender and by quantitatively cutting out and crushing the resultant dry coal to enhance blend accuracy, bulk density and coal grinding efficiency. CONSTITUTION:For example, coal of each description conveyed from coal yard is dried in a rotary multipipe heat exchange type coal dryer so that the water content at the exit of said dryer represents constant value 6% followed by storage in respective blender. In such blender, the corresponding coal is quantitatively cut out at the respectively specified blend ratio, being crushed in the respective crusher followed by mixing in a coal mixer and feeding to the coal tower in a coke oven. The initial water content of the coal of each description should have been set at a value determined by the respective coal-drying capability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for drying coking coal to be charged into a coke oven coal tower.

[Conventional technology]

Coking coal charged into a coke oven usually contains about 8 to 10% moisture. When this coking coal is dried and charged into a coke oven and carbonized, it has the following effects: 1) Reduction in the amount of heat of carbonization, 2) Increased productivity, and 3) Improved quality (increased coke strength).

Conventionally, the process for drying raw coal has been as shown in Figure 2.

In Figure 2, each coal brand transported from the coal yard by a belt conveyor is stored in a blending tank, cut out at a fixed amount (T/L) at a target blending ratio, and then crushed by a coal crushing machine. It is dried in a dryer to a constant moisture content (6%) and sent to a coke oven. However, each blending tank is determined based on the required dry amount (T) based on the moisture percentage set for each coal brand.
/L). This moisture setting is only set by actually measuring it once for 7 days, and currently it is not possible to absorb mix-up errors in cutting due to short-term moisture fluctuations.

The main factors for moisture fluctuations include 1) rainfall, and 2) the payout position of each coking coal MM in the yard.

Such moisture fluctuations cause adverse effects such as a decrease in blending accuracy, variations in coke strength and coke quality, and an increase in the amount of heat consumed in a coke oven.

[Problem that the invention seeks to solve]

The present invention aims to overcome the drawbacks of the conventional coking coal drying method as described above.

In other words, a coal dryer is installed before entering the blending tank, and by absorbing short-term moisture fluctuations with the dryer, coking coal with a constant moisture content is supplied to each blending tank, improving blending accuracy. At the same time, the purpose is to obtain effects such as 1) reduction in blending tank inventory, 2) reduction in M feeding cost I, and 3) increase in coal crushing efficiency.

[Means for solving problems]

In the present invention, drying of coking coal (moisture content 9% to 6%) was conventionally carried out before charging it into a coke oven coal tower, but in the present invention, it is carried out before it is charged into a blending tank. .

That is, in the present invention, when charging coking coal from a coal yard to a coke oven, a coal dryer is installed in front of a blending tank, and after drying the coking coal to a constant moisture content, it is stored in the blending tank, and the dry coal is transferred to the blending tank. This is a drying method for coking coking coal, which is cut and crushed at regular intervals and, if necessary, mixed and then charged into a coke oven coal tower.

[Effect]

In this way, according to the coking coal drying method of the present invention, a coal dryer is installed before the blending tank, so even if there is a short-term moisture fluctuation, it is absorbed by the dryer and the coal drying process is always maintained for each brand that is in the blending tank. It is possible to control the moisture content of the product at a constant level, which improves blending accuracy. At the same time, it has the following effects: 1) power source for transportation of coking coal after the coal dryer, 2) increase in effective inventory in blending tank, 3) increase in coal powder efficiency.

〔Example〕

FIG. 1 shows a process diagram based on an embodiment of the present invention. As shown in the figure, a coal dryer was installed before the blending tank, and a coal crusher was installed after the blending tank.

In the figure, t coal of each brand (also = 9%, σ: 1.5%, number of brands = 15) is transported from a coal yard by a belt conveyor to a coal dryer (rotary multi-tube heat After being dried to a constant moisture content of 6% at the dryer outlet using an exchangeable type S, T, and D type (capacity 260T/H), it is stored in each blending tank.

In the blending tank, a fixed amount of coal is cut out at a target blending ratio, crushed in a coal crusher, mixed in a coal mixer, and sent to a coke oven coal tower. The moisture setting for each brand is set to a value determined from the coal dryer onwards.

As a result of using the above drying method, compared to the method using the process shown in Figure 2, 1) Blending accuracy was improved, variation in coke strength was reduced, and average Dr So was improved by 0.5%. .

2) The angle of repose decreases with a decrease in mean moisture and variation;
The bulk density has increased and the effective inventory rate has increased by 6 to 7%.

3) Reduction in transportation power 4) Increased coal crushing efficiency enabled power savings.

〔Effect of the invention〕

The coking coal drying method of the present invention adjusts the moisture content at the outlet of the coal dryer to 6%, thereby: (1) improving blending accuracy to reduce variation in coke strength; improves.

(2) Increased effective rF of the mixing tank once (3) Reduction of transportation power (4) Increased coal crushing efficiency It has the following effects.

[Brief explanation of drawings]

FIG. 1 is a process diagram of the method of the present invention, and FIG. 2 is a process diagram of the conventional method.

Claims (1)

[Claims] When charging coking coal from the coal yard to the coke oven,
A method for drying coke coking coal, characterized in that a coal dryer is installed in front of a blending tank, the raw coal is dried to a constant moisture content and then stored in the blending tank, and a fixed amount of dry coal is cut out from the blending tank and crushed.