JPH11286689A - Coal thermal decomposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the formation of deposits in a rapid thermal decomposition reactor of coal which takes place, when the coal throughput is lowered and causes troubles with the operation of the reactor. SOLUTION: In the coal thermal decomposition process by a coal thermal cracking reactor comprising a high temperature gas generating zone 2 using coal or char as the fuel and having, at its bottom, a slag discharge opening 8 for discharging molten slag; and a coal cracking reaction zone 1 provided above the high temperature gas generating zone to which pulverized coal is supplied and mixed with the high temperature gas 6 from the high temperature gas generating zone, by measuring the pressure from a pressure measuring opening 19 provided in the upper part of the reactor, the flow rate within the reactor is maintained by controlling the pressure to the value proportional to the increase or decrease of the amount of coal or char supplied to the high temperature gas generating zone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coal pyrolysis method for heating coal in a gas phase to obtain a fuel gas, tar and solid char as a pyrolysis product.

[0002]

2. Description of the Related Art Conventionally, a method using a fluidized bed or a rotary kiln has been used for coal pyrolysis. However, this method has a problem in that rapid heating cannot be performed and the yield of volatile components (gas / tar), which is a useful component, is low.
To this end, the present inventors have disclosed in Japanese Patent Application Laid-Open No. 5-295371 that a portion of a char obtained by rapidly heating coal is gasified with oxygen in a high-temperature gas generating section, and is provided above the high-temperature gas generating section. A method for pyrolyzing coal by blowing pulverized coal into a high-temperature gas generated from a high-temperature gas generating section in a coal pyrolysis reaction section by airflow conveyance is presented.

[0003]

Problems to be Solved by the Invention
In the coal pyrolysis according to the method presented in Japanese Patent Publication No. 1 (Kokai), rapid pyrolysis reaction of coal can be performed by mixing a high-temperature gas and pulverized coal transported in a gas stream in a gas bed. A high-temperature gas is sent upward from the bottom of the reactor as a reactor enabling the reaction, and the pyrolysis coal is blown into the high-temperature gas by several nozzles from the lower side of the reactor to perform rapid heating. This rapid heating causes the coal particles to undergo a pyrolysis reaction, producing fuel gas, tar, and solid char.

[0004] In this process, the temperature in the coal pyrolysis reaction section is determined by the gas temperature in the high-temperature gas generation section, the gas amount, and the amount of coal fed into the coal pyrolysis reaction section. Therefore, in order to reduce the amount of coal processing (the amount of coal pyrolysis) in the process, it is necessary to reduce the amount of gas generated from the high-temperature gas generation unit in accordance with the reduction in the amount of coal processing in the coal pyrolysis reaction unit. is there. When the amount of gas from the high-temperature gas generation section decreased, the coal charged into the coal pyrolysis reaction section adhered to the inside of the coal pyrolysis reaction section, causing troubles such as blockage of the pyrolysis coal input port.

Accordingly, the present invention provides a coal pyrolysis method capable of solving the above-mentioned problems and easily adjusting the amount of coal pyrolysis.

[0006]

The cause of the formation of deposits inside the coal pyrolysis reaction section is that the injected coal collides with a wall at around 500 ° C. where the coal enters a softened and molten state. Solid particles (chars) exceeding the temperature do not have an adhesive property and do not become an attached matter. Since the formation of deposits was observed when the amount of coal treatment was reduced, such as during turndown,
Investigation of the relationship between the flow rate of high-temperature gas upward in the reactor and the amount of deposits produced revealed that the amount of deposits generated did not occur when the high-temperature gas flow rate in the reactor was maintained at a certain flow rate or higher. I understood. At a flow rate lower than that, the mixing of the finely pulverized coal stream and the high-temperature gas stream charged into the coal pyrolysis reaction section becomes insufficient, and the pyrolysis target temperature of 700 to 900 ° C.
The temperature of the coal particles does not reach the surface of the reactor and collides with the reactor wall to form deposits.

[0007] When the throughput of coal is reduced, the pressure in the reactor is lowered to secure a flow rate, so that the mixing of the coal particles and the high-temperature gasified gas is favorably maintained and the temperature of the particles is rapidly increased. This makes it possible to prevent coal from adhering in the coal pyrolysis reaction section.

As described above, the present inventors have investigated the conditions under which deposits are formed inside the reactor, and as a result, have found that deposit formation is closely related to the flow rate in the reactor. The invention has been completed for a method in which generation does not occur.

According to the coal pyrolysis method of the present invention, coal or char is used as a fuel, and a high-temperature gas generating section having a slag discharge port at the bottom for discharging molten slag, and pulverized coal is supplied to an upper portion of the high-temperature gas generating section. And a coal pyrolysis method using a coal pyrolysis apparatus comprising a high-temperature gas from the high-temperature gas generating section and a coal pyrolysis reaction section for mixing pulverized coal,
The pressure is measured from a pressure measurement port provided in the coal pyrolysis reaction section, and the pressure is controlled so as to be a value proportional to an increase or decrease in the supply amount of coal or char to the high-temperature gas generation section,
The flow rate in the coal pyrolysis reaction section is maintained.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a coal pyrolysis apparatus according to an embodiment of the present invention, showing the apparatus flow. As shown in FIG. 1, the coal pyrolysis apparatus includes a high-temperature gas generating section (gasification furnace) 2 having a slag discharge port 8 and a gasification burner 7 for discharging molten slag at the bottom, and pulverized coal (pyrolysis coal).
4, the high-temperature gasification gas 6 from the high-temperature gas generator 2 and the pyrolysis coal 4 are mixed, and a high-temperature gas supply port (throat section 3) is provided at a lower portion, a product outlet 9 is provided at an upper portion, and a pyrolysis coal is provided at a side wall. It has a supply port 10. The pyrolysis apparatus is composed of such a coal pyrolysis reaction section 1, a high-temperature gas generation section 2, and a throat section 3 therebetween. In the high-temperature gas generating section 2, coal or char is gasified with oxygen or air, and CO, H
₂ , high-temperature gas mainly composed of CO ₂ and H ₂ O is generated,
The ash in the coal and char becomes molten slag and is discharged from the slag discharge port 8 to the outside of the coal pyrolysis apparatus.

1400 generated in the high-temperature gas generator 2
The high temperature gas of about 1700 ° C. is sent to the coal pyrolysis reaction section 1 through the throat 3. In the coal pyrolysis reaction section 1, the coal to be pyrolyzed is finely pulverized and then supplied from the pyrolysis coal supply port into the coal pyrolysis reaction section and the high-temperature gasified gas 6 from the high-temperature gas generation section and the coal pyrolysis. It is mixed in the lower part of the reaction section. The mixture of the high-temperature gas 6 and the pyrolysis coal 4 rapidly heats the pyrolysis coal 4 to cause a pyrolysis reaction, thereby generating pyrolysis products such as fuel gas, tar, and solid char. This pyrolysis product is discharged from a product outlet 9 above the coal pyrolysis reaction section 1 in a state of being mixed with the gasification product gas 6. Among the discharged pyrolysis products, the solid char is separated by the cyclone 11 and stored in the char tank 15, and then discharged as the gasification char 14 and the product char 16. The gasification char is supplied to the high-temperature gas generator 2 from a gasification char supply hopper. The product stream from which the solid char has been removed is tar-removed by the tar collector 20 and becomes only fuel gas. The degree of opening of the pressure regulating valve 12 installed after the tar collecting device 20 is determined by the weight reduction of the gasification char supply hopper 21.
(4) By adjusting the pressure measured by the pressure measuring port and the pressure measuring device 19 attached to the coal pyrolysis reaction section 1 in accordance with the decrease of the supply amount by the controller 18 so as to have the same decreasing ratio, the coal heat It is possible to maintain the flow state of gas and particles inside the decomposition reaction section 1.

[0013]

[Example] Coal pyrolysis test showed that the pulverized coal supply was 30
The test was carried out using a large test apparatus of 0 kg / h. This large-sized test apparatus has a structure similar to the apparatus schematic diagram of FIG. The pyrolysis reaction conditions in the coal pyrolysis reaction section are as follows.
The gasification conditions in the high-temperature gas generating section at 0 ° C. and a pressure of 3 atm are a temperature of 1550 ° C. and a pressure of 3 atm. The amount of pulverized coal supplied to the coal pyrolysis reactor is 100 to 200 kg / h, and the amount of char supplied to the high temperature gas generator is 50 to 100 kg / h. The pulverized coal used was coal A (Indonesian coal), with an average particle size of about 40 microns.

The test was conducted by changing the gasification char supply amount and the flow rate in the coal pyrolysis reaction section, and after the test was completed, the reactor was disassembled and the amount of deposits was measured. Table 1 shows the test results. Pyrolysis coal supply under standard conditions 300 kg /
h and the pressure in the coal pyrolysis reaction section was reduced to the same reduction ratio as the reduction in the amount of char supplied to the high-temperature gas generating section under the conditions 1 and 3, where the coal pyrolysis reaction section was used. No deposit formation was observed in the sample No. 1, and the formation of deposits was observed when the pressure was increased. From this result, it can be seen that in order to prevent the formation of deposits, it is necessary to reduce the pressure in the coal pyrolysis reactor at the same ratio as the reduction ratio of the gasification char supply amount.

[0015]

[Table 1]

[0016]

According to the coal pyrolysis operation method of the present invention,
Rapid pyrolysis of coal using a gas stream layer can be performed inside the coal pyrolysis reactor without adhesion trouble due to softening and melting of coal when the throughput of coal is reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an apparatus flow in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coal pyrolysis reaction part 2 High-temperature gas generation part 3 Throat 4 Pyrolysis coal 5 Thermal decomposition product 6 High-temperature gasification gas 7 Gasification burner 8 Molten slag outlet 9 Thermal decomposition product outlet 10 Pyrolysis coal inlet 11 Gas / steam inlet 12 Pressure regulating valve 13 Oxygen gas, steam 14 Gasification char 15 Char tank 16 Product char 17 Product gas 18 Controller 19 Pressure measurement port and pressure measurement device 20 Tar recovery device 21 Gasification char supply hopper

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 000002118 Sumitomo Metal Industries Co., Ltd. 4-5-33 Kitahama, Chuo-ku, Osaka-shi, Osaka (71) Applicant 000004123 Nippon Kokan Co., Ltd. 1-1-1, Marunouchi, Chiyoda-ku, Tokyo No. 2 (72) Inventor Hiroyuki Kosui Ryu 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division (72) Inventor Takafumi Kawamura 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division (72) Inventor Shigeru Hashimoto 20-1 Shintomi, Futtsu City Nippon Steel Corporation Technology Development Division (72) Inventor Masaki Onoda 20-1 Futtsu City Shintomi Technology Development Division Nippon Steel Corporation

Claims (1)

[Claims] 1. A high-temperature gas generating section having coal or char as fuel and having a slag discharge port for discharging molten slag at the bottom thereof, and supplying pulverized coal to an upper portion of the high-temperature gas generating section to supply the pulverized coal to the high-temperature gas generating section. In a coal pyrolysis method using a coal pyrolysis apparatus comprising a high-temperature gas and a coal pyrolysis reaction section that mixes pulverized coal, a pressure is measured from a pressure measurement port provided in the coal pyrolysis reaction section, A coal pyrolysis method, wherein the pressure is controlled so as to be a value proportional to an increase or a decrease in the amount of coal or char supplied to a high-temperature gas generation section, and a flow rate in the coal pyrolysis reaction section is maintained.