JPH07331256A - Method for operating rapid thermal cracking of coal - Google Patents

Abstract

PURPOSE:To increase the yield of reactional product (especially tar producing amount) by a relatively simple means in an operating method of rapid thermal cracking of coal for generating high-temperature gas in a gasification furnace of coal and char and then mixing pulverized coal and the high-temperature gas in a thermal cracking reactor. CONSTITUTION:This method for operating rapid decomposed process of coal comprises adding >=1kg and <=20kg steam based on 10kg coal weight into the lower part of a thermal cracking reactor or a high-temperature gas of a gasification furnace. Thereby, the residence time of a thermal cracking product in the reactor is decreased and secondary decomposition reaction of the product is suppressed and tar yield is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention mixes coal with high-temperature gas and raises the temperature to cause a thermal decomposition reaction to generate a fuel gas.
It relates to a method for controlling products in a method for obtaining tar char.

[0002]

2. Description of the Related Art As a rapid thermal decomposition process of coal, the process described in Japanese Patent Laid-Open No. 05-295371 can be mentioned.

In this process, finely pulverized coal is mixed with high-temperature gas to heat the coal and cause a thermal decomposition reaction.

The high-temperature gas is characterized by being obtained by partially burning solid char produced by thermal decomposition with oxygen.

Pyrolysis reaction temperature is mentioned as a condition for changing the product, and when the pyrolysis temperature rises, the pyrolysis of coal is promoted, and the gas yield increases and the tar yield decreases. .

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In 5371, when it is desired to change the product yield / property, regarding the residence time of gas / particles in the furnace, which greatly affects the product yield / property other than the thermal decomposition temperature, the amount of coal input The only way to change it is to change the amount of gasification of char or char or change the size of the furnace.

An object of the present invention is to obtain an increased tar yield (increased chemical raw materials) by shortening the particle / gas residence time in the furnace.

[0008]

The present invention provides a method for operating rapid coal pyrolysis in which a high temperature gas is generated in a coal char gasifier and finely pulverized coal and the high temperature gas are mixed in a pyrolysis reactor. , 1 kg or more per 10 kg of coal weight in the pyrolysis reactor or high temperature gas of the gasifier 2
The feature is that water vapor of 0 kg or less is added.

[0009]

[Operation] In the thermal decomposition reaction of coal, the primary reaction stage in which volatile components are removed from the coal in the initial stage of the reaction, and the generated volatile components are further decomposed by receiving heat in the thermal decomposition reactor, It can be divided into the stages of secondary reactions that change to lighter components.

When the residence time of the gas or particles inside the thermal decomposition reactor is long, the gas yield of the product is increased and the tar yield is decreased due to the secondary reaction. Further, regarding the properties of the produced tar, the 1,2-ring component increases when the residence time is long, and the 2,3-ring component and the aliphatic component increase when the residence time is short.

In the conventional method, the amount of pyrolysis treatment is increased to increase the amount of volatile matter produced and the residence time is shortened.

In the present invention, by introducing steam into the pyrolysis reactor or the gasification furnace, the amount of gas passing through the pyrolysis reactor portion is increased, whereby the retention of particles / gas in the reactor. The time can be adjusted to be short, and it is possible to increase the yield of the 2.3-ring component, which is the characteristic tar component from coal.

FIG. 1 shows an example of a flow sheet of a coal pyrolysis process using the present invention.

The char generated by pyrolysis of coal is partially burned with oxygen in a hot gas generator, and the hot gas obtained is used to pyrolyze coal in a pyrolysis reactor.

Char is recovered from the generated gas by a cyclone, then heat is recovered from the gas by a gas heat recovery device, and tar is recovered by a tar recovery device, followed by gas purification.

The steam is introduced into the char gasification furnace near the pyrolysis coal charging port in the lower part of the pyrolysis reactor or in the char gasification furnace to increase the generated gas volume.

As the steam, it is possible to use steam utilizing heat recovered from the furnace wall of the gasification furnace, the produced gas, char, or the like.

When a gas such as nitrogen which is not involved in the reaction is introduced into the reactor, there is a problem that the calorific value of the produced gas is lowered. What is separable is preferable.

In this respect, when steam is used, it is possible to condense and collect it together with the tar outside the reactor, and there is an effect that the calorific value of the produced gas is not reduced. When the amount of steam added is less than 1 kg with respect to the weight of coal to be thermally decomposed of 10 kg, there is almost no change in the residence time.
No change in product yield was observed, and if the amount of steam added was more than 20 kg with respect to the weight of coal of 10 kg, it was impossible to form a uniform thermal decomposition reaction in the reactor.

The same effect can be obtained by further sending the produced gas to the thermal decomposition reactor in the sense that the calorific value of the produced gas is not reduced.

[0021]

EXAMPLE As an example of the present invention, a case where an apparatus having a coal throughput of 1 t / d is used is shown. FIG. 2 shows the relationship between the pyrolysis product yield and the gas residence time in the reactor.

If the residence time of the gas in the reactor decreases, the tar decomposition does not proceed and the tar yield increases.

In the present invention, when the gas residence time in the steam-free pyrolysis reactor is 3 seconds, 200 ° C. steam is added to 2
By supplying 0 kg / h, the gas residence time becomes 2 seconds,
Tar yield increases by more than 10%.

FIG. 3 shows the ratio of the number of constituent rings in the tars obtained by the conventional method carried out at a coal pyrolysis temperature of 700 ° C. and the method of the present invention.

The number of rings in the tar is about 70% by weight of the components of three or more rings in the total tar in the conventional method having a gas residence time of 3 seconds, whereas the decomposition of the tar component proceeds in the method of the present invention. No, it is possible to change the obtained tar component by increasing the amount of the components having 3 or more rings by about 20%.

[0026]

EFFECTS OF THE INVENTION According to the present invention, it is possible to shorten the gas retention time in the thermal decomposition reactor without replacing the main body of the thermal decomposition reactor, and it is possible to change the properties of the tar produced. .

[Brief description of drawings]

FIG. 1 shows a coal pyrolysis process flow in the present invention.

FIG. 2 shows the relationship between the gas residence time in the pyrolysis reactor and the product yield.

FIG. 3 shows the ratio of the number of constituent rings of tars obtained by the method of the present invention and the conventional method.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Hashimoto 20-1 Shintomi, Futtsu City, Chiba Shin Nippon Steel Co., Ltd.

Claims (1)

[Claims] 1. A method for operating rapid coal pyrolysis in which high temperature gas is generated in a coal / char gasifier and finely pulverized coal and high temperature gas are mixed in the pyrolysis reactor, in the pyrolysis reactor or in the gas. A method for operating rapid coal pyrolysis, characterized in that 1 kg or more and 20 kg or less of steam is added per 10 kg of coal in the high temperature gas of the gasification furnace.