JPH05163490A - Production of char by rapid thermal decomposition of coal - Google Patents

Abstract

PURPOSE:To obtain char suitable for solid fuel having an excellent ignition temperature by increasing and decreasing a circulating gas so as to make a fuel ratio of char into a specific ratio, controlling temperature in a char vessel and separating char from gas tar char in a high-temperature state. CONSTITUTION:In a process of producing gas tar char by thermally decomposing coal rapidly, coal 1 is mixed with a heated circulating gas by a reactor 3 of thermally decomposing gas rapidly to give a high-temperature formed gas (including tar vapor) and char, these formed products are introduced through a heat exchanger 4 to a char vessel 5, the temperature in the char vessel 5 is regulated so as to make a fuel ratio of char <=2.5 by increasing and decreasing a flow rate of the circulating gas for cooling and the residual circulating gas is sent to the heat exchanger 4 to give the objective char having excellent performance as a solid fuel having excellent combustibility.

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 volatile matter contained in the fuel is about 10% when the fuel ratio, which is the ratio of the volatile matter in the fuel to the fixed carbon, is about 4 to 7, Fuel ratio level normally used for pulverized coal boilers (1
.About.2.5), and when used in a boiler, there are problems such as the generation of NOx and unburned components, and the combustibility is poor.

[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 circulating gas 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 3 to generate high-temperature generated gas (including tar vapor) and char.

These products pass through a heat exchanger 4 from a coal rapid pyrolysis reactor to a char vessel (char and gas.
It is introduced into a container for separating tar) 5.

This char vessel is cooled by circulating gas and kept at about 350.degree. The high boiling point component in the tar is condensed on the char particles by cooling the char vessel.

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 so that the fuel ratio becomes 2.5 or less and the flow rate of the circulating gas for cooling is adjusted. The remaining circulating gas is sent to the heat exchanger without passing through the char vessel.

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. Char Vessel temperature 350
At above ℃, the tar component adhering to char is small and the fuel ratio exceeds 2.5. From this figure, it is understood that the operation of the Cher-Vessel temperature should be performed at 350 ° C or lower.

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 charvessel rises above 350 ° C., the fuel ratio of 2.5 or less can be achieved by increasing the flow rate of the circulating gas flowing through the charvessel and lowering the temperature of the charvessel.

The comparison of the fuel ratio of chars obtained by the method of the present invention with the charcoal obtained by the conventional method using the same kind of coal as that of the embodiment is shown in Table 1, and the results of the flammability measurement test of the char. 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 becomes a large value of 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 400 ° C.,
In Examples B and C controlled at 350 ° C, a large amount of volatile components remained in the char, the fuel ratio was around 2, and the combustibility was improved.

[0020]

[Table 1]

[0021]

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 graph showing the relationship between the temperature of the char vessel and the fuel ratio.

FIG. 2 is an explanatory view of the rapid coal pyrolysis process of the present invention.

FIG. 3 is an explanatory diagram showing an example of an operating state of the embodiment.

FIG. 4 is a diagram comparing the combustibility of each substance.

[Explanation of symbols]

 1 coal 2 circulating gas heater 3 coal rapid pyrolysis reactor 4 heat exchanger 5 char vessel 6 tar recovery device 7 circulating blower

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[Procedure amendment]

[Submission date] January 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0019

[Correction method] Change

[Correction content]

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.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

[0020]

[Table 1]

Claims (1)

[Claims] 1. A rapid thermal decomposition of coal to produce gas tar.
In the process of manufacturing char, gas
When separating char from tar / char, the char gas by rapid coal pyrolysis is characterized by adjusting the temperature inside the char vessel by increasing / decreasing the amount of circulating gas so that the fuel ratio of char is 2.5 or less. Method.