JPS5930895A - Modification of coal - Google Patents

Abstract

PURPOSE:To make a low-grade coal into higher-Btu one, by adding an oil as the binder to an aqueous slurry of pulverized coal to prepare a deashed granulated coal followed by dry distillation of the coal to recover and remove through extraction the oil and water contained, respectively, to reduce both the ash and water contents. CONSTITUTION:A low-grade coal 1 is subjected to a pulverizer 2 to make a finely-ground one, followed by mixing with water into an aqueous slurry, which is then fed to the granulator 3, where an oil 4 is added as the binder to form a granulated coal 6 while eliminating the ash 5 contained. The resulting coal 6 is then subjected to dry distillation in the corresponding unit 7 under normal pressures at 200-500 deg.C where the oxygen-contg. bound groups such as OH and COOH will be decomposed, to recover as the binder and remove through extraction the oil 4 and water 8 contained, respectively, thus obtaining the objective modified coal 9 of higher Btu-value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coal reforming method, and in particular to a coal reforming method suitable for reforming low-grade coal that can be deashed and granulated without carbonization into coal with increased calories. This relates to a modification method.

Low-grade coal, such as lignite and sub-bituminous coal, contains more ash and water than bituminous coal, which is high-grade coal, so it is low in calories and easy to handle.

The disadvantage is that combustion efficiency is poor. Therefore, in order to effectively utilize such low-rank coal, it is important to perform deashing and dewatering operations on the low-rank coal to reduce its ash and water content and reform it into coal with increased calories. .

However, currently, the use of high-grade coal is leading, and decarbonization is possible. Despite the abundance of low-rank coal, the development of reforming technology for low-rank coal has remained largely untouched.

An object of the present invention is to provide a method for reforming coal that can be reformed into low-rank coal with increased calories by reducing the ash content and water content.

The features of the present invention include the steps of pulverizing coal, mixing water with the pulverized coal to form an aqueous slurry, and adding oil as a binder to this aqueous slurry to decalcify and granulate it. It consists of a step of forming granulated coal, a step of dry distilling the granulated coal to extract oil and moisture, and a step of recovering the extracted oil as a binder. The purpose is to reduce the water content and reform the coal into a coal with increased calories.

An embodiment of the present invention will be described with reference to the drawings.

In the drawing, coal, for example low rank coal, is pulverized fi2
After being pulverized, water is mixed to form an aqueous slurry, which is supplied to the underwater granulation device 3. Oil 4 is added as a binder to the aqueous slurry supplied to the underwater granulator 3, and the slurry is deashed and granulated. As a result, ash 5 is removed and granulated coal 6 is formed. This granulated coal 6 is produced by carbonization device U7.
Carbonization is carried out under normal pressure at a temperature range of 200°C to 500°C at which oxygen-containing bonding groups such as -OH and -COOH groups are decomposed. As a result, water 8 is extracted and removed, and the extracted oil 4 is recovered as a binder. As a result, the ash content and moisture content are reduced, and a modified coal 9 with increased calories can be obtained.According to this example, the ash content and moisture content are 19%.

When 21% low rank coal was reformed, the following results were obtained.

First, the above-mentioned low-rank coal was pulverized to a size of -74 μm and 80%, water was mixed with this to form an aqueous slurry, and 20% of oil was added as a binder to demineralize the slurry. As a result, granulated coal containing ash and water content of 7% and 21% was obtained. Thereafter, 20 granulated coals were carbonized under normal pressure and at a temperature of 400°C, and as a result, the ash and moisture content was 11%.
9%, thus obtaining modified coal with increased calories. In this case, 20% of the oil is added as a binder to the aqueous slurry, so 20% of the oil is extracted from the oil that forms the granulated coal (the oil added as a binder) and the oil of the low-grade coal during carbonization. 2 were recovered.

The coal reforming method as in this embodiment can provide the following effects.

(1) After coal is deashed and granulated to form granulated coal, this granulated coal is carbonized, so the ash content and moisture content are reduced, resulting in modified coal with increased calories. .

(2) Since the oil added to the aqueous slurry as a binder is the oil extracted and recovered by carbonization of granulated coal,
In addition to homogenizing oil quality, oil content can be extracted by carbonization1.
Collection can be performed efficiently.

(3) Since the oil content of the granulated coal is not entirely extracted and recovered by carbonization, the moisture-proof property of the modified coal can be maintained well and it can be prevented from being pulverized.

As explained above, the present invention comprises a step of pulverizing coal, a second step of mixing water into the pulverized coal to form an aqueous slurry, and a step of adding oil as a binder to this aqueous slurry to remove the coal. The method consists of a step of granulating ash to form granulated coal, a step of dry distilling the granulated coal to extract oil and moisture, and a step of recovering the extracted oil as a binder. This reduces the ash content and moisture content of low-rank coal, which has the effect of reforming it into low-rank coal with increased calories.

[Brief explanation of drawings]

The drawing is a process diagram 70 illustrating an example of a coal reforming process embodying the present invention.

Claims (1)

[Claims] 1. A step of pulverizing coal, a step of mixing water with the pulverized coal to form an aqueous slurry, and adding oil as a binder to the aqueous slurry to demineralize it. a step of carbonizing the granulated coal to extract oil and moisture; and a step of recovering the extracted oil as the binder. Modification method. 2. The carbonization is carried out under normal pressure and at 200°C to 50°C.
The method for reforming coal according to claim 1, which is carried out in a temperature range of 0°C. 3. The coal reforming method according to claim 1, wherein the amount of oil extracted from the granulated coal and recovered as a target binder is at least the amount of oil added to the aqueous slurry.