JPH05194958A - Production of coal char - Google Patents

Abstract

PURPOSE:To produce char excellent in the performance as a solid fuel of good combustibility in obtaining char by rapidly pyrolyzing coal. CONSTITUTION:The objective production process is to rapidly pyrolye coal for producing gases, tar and char, wherein the inside temperature of the char vessel is regulated by increasing or decreasing the amount of cooling water so that the fuel ratio of char may be 2.5 or below in separating char from the gas, tar and char at high temperature. The combustibility of the formed char can be readily heightened by using a heavy tar which is of low value among the products, and its scope of application can be widened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing char which can be used as a solid fuel having good ignitability when producing gas tar char by rapidly pyrolyzing coal.

[0002]

2. Description of the Related Art In the conventional rapid coal pyrolysis method, since the purpose is to obtain a large amount of tar and gas, char is separated from gas (including tar vapor) at a high temperature of about 500 ° C. It is used.

For example, in Japanese Patent Laid-Open No. 1-131491, by coal-mixing coal in a gas phase with a high temperature gas, the coal is pyrolyzed in a short time, and most of the volatile components in the coal are converted to tar gas. Techniques for collecting are disclosed.

By the rapid thermal cracking of the coal in the air-flow bed, it is possible to obtain tar up to 10 times as much as that of a conventional coke oven, which is a conventional thermal cracking technology for coal.

Coal is comminuted and introduced into the reactor where it is mixed with the hot product gas. This gas is obtained by circulating the produced gas and heating it in a heat exchanger, a heat storage furnace, or the like.

[0006]

In the char produced by the above method, the fuel ratio, which is the ratio of volatile matter in the fuel to fixed carbon, is about 4 to 7, and the volatile matter contained is around 10%. However, the fuel ratio is considerably higher than the fuel ratio level (1 to 2.5) normally used for pulverized coal boilers, and when used in boilers, there are problems such as generation of NOx and unburned components, resulting in poor combustibility.

[0007]

The method for producing char by rapid pyrolysis of coal according to the present invention is a process for producing gas tar char by rapidly pyrolyzing coal. When separating the char
It is characterized in that the temperature in the char vessel is adjusted by increasing or decreasing the amount of cooling water so that the fuel ratio of char becomes 2.5 or less.

[0008]

The present invention will be described in detail below with reference to FIG.
FIG. 2 is a flow sheet of the rapid coal pyrolysis process of the present invention.

The coal 1 is mixed with the heated circulating gas in the coal rapid pyrolysis reactor 2 to produce gas (including tar vapor) and char.

These products are used in the coal rapid pyrolysis reactor 2
It is further introduced into a char vessel (container for separating char and gas / tar) 4 through a heat exchanger 3. This char vessel is cooled with cooling water and kept at about 350 ° C.

By cooling the char vessel, the high boiling point components contained in the tar vapor in the gas are condensed on the char particles.

Since the relationship between the fuel ratio of the char produced and the char vessel temperature varies depending on the coal used, a graph of the temperature inside the char vessel and the fuel ratio is prepared in advance according to the type of coal used.

Then, the temperature in the char vessel is adjusted by the flow rate of the cooling water so that the fuel ratio becomes 2.5 or less.

When the combustion ratio is 2.5 or more, when used in a pulverized coal boiler, the amount of NOx produced increases and dust is produced, which is not a method for producing char with good combustion performance.

[0015]

EXAMPLE FIG. 1 shows an example of the relationship between the char vessel temperature and the obtained char fuel ratio as a result of the experiment conducted by the present inventors.

When the char vessel temperature exceeds 350 ° C., the tar component adhering to the char is small and the fuel ratio exceeds 2.5. From this figure, the operation of the Cher-Vessel temperature is 350 ° C.
Do the following:

FIG. 3 shows an example of the operating state in this case. The operation is carried out under the condition that the fuel ratio is 2.5 or less, that is, the temperature of the Charbessel temperature is 350 ° C. or less.

When the temperature of the charbessel rises above 350 ° C., the fuel ratio of 2.5 or less can be achieved by increasing the flow rate of the cooling water flowing through the charbessel and lowering the temperature of the charbessel to 350 ° C. or lower.

Table 1 shows a comparison of the fuel ratios of chars obtained by the method of the present invention and the charcoal obtained by the conventional method using the same kind of coal as those of the example, and the results of the flammability measurement test of the chars. Is shown in FIG.

In the conventional method (A) in which the char recovery temperature is not controlled, only about 10% of the volatile matter remains in the char, and the fuel ratio is as large as 7.5, and the combustibility is the same as that of conventional coal. It is lower than the comparison.

On the other hand, the char recovery temperature is 300 ° C.
In Examples B and C controlled at 250 ° C, a large amount of volatile components remained in the char, the fuel ratio was around 2, and the combustibility was improved.

[0022]

[Table 1]

[0023]

INDUSTRIAL APPLICABILITY According to the rapid pyrolysis of coal of the present invention, the char produced is a simple process, and the heavy tar, which has a low value among the products, is used to increase the flammability of the produced char and its use. Can be expanded.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a temperature of a Chervessel and a fuel ratio.

FIG. 2 shows an outline of a flow sheet of the present invention.

FIG. 3 is a diagram showing an example of a manufacturing operation state of a coal char using the method of the present invention.

FIG. 4 is a diagram showing the relationship between char / coal burning time and efficiency.

[Explanation of symbols]

 1 Coal 2 Rapid coal pyrolysis reactor 3 Heat exchanger 4 Char vessel 5 Tar recovery device 6 Product gas 7 Circulating blower 8 Circulating gas heater 9 Cooling water 10 Drainage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Iida 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division

Claims (1)

[Claims] 1. A rapid thermal decomposition of coal to produce gas, tar,
In the process of producing char, gas at high temperature,
A method for producing coal char, characterized in that, when separating char from tar and char, the cooling water amount is increased or decreased so that the fuel ratio of char is 2.5 or less, and the temperature inside the char vessel is adjusted.