JPH07188677A - Vertical coal pyrolyzer - Google Patents

Abstract

PURPOSE:To provide a vertical coal pyrolyzer whereby desired component gases can efficiently and selectively be recovered from pyrolysis gases generated from coal by pyrolysis alone without the necessity for any accessories. CONSTITUTION:The pyrolyzer consists of a vertical coal pyrolysis zone 13, means 14a to 14d for heating partitioned pyrolysis sections 13a to 13d to temperatures corresponding to the formation temperatures of the respective desired component gases and having a temperature gradient at which the pyrolysis of the coal C proceeds from the top of the pyrolysis zone 13 to its bottom, means 16a to 16d provided in the respective pyrolysis sections 13a to 13d and used for recovering the desired component gases and a means 20 provided below the pyrolysis zone 13 and used for gasifying the coal pyrolysis residue CR into a high-temperature gas. The high-temperature gas is used to heat the pyrolysis sections 13a to 13d.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coal pyrolysis apparatus for pyrolyzing coal to selectively recover a desired component gas of the pyrolysis gas.

[0002]

2. Description of the Related Art Coal produces various gases including high-calorie gas by thermal decomposition (carbonization). For example, in a coke oven, the main components of pyrolysis gas generated from coal with the progress of pyrolysis are water, tar, higher hydrocarbons (for example, ethane and ethylene), methane, carbon monoxide, carbon dioxide gas, hydrogen. Changes to.

However, in the coke oven, all of the above component gases are collected in the same riser pipe, and the coke oven gas obtained is a mixture of these component gases. Therefore, for example, when a high-concentration hydrogen gas, which is used in the chemical industry, semiconductor industry, food industry, petroleum refining, etc. and is expected to be used as clean energy in the future, is to be obtained from this coke oven gas, gas purification for that purpose Equipment is required separately.

Further, coke oven gas has the highest calorie of the by-product gas in the steel mill, but its lower calorific value is at most about 4,620 kcal / Nm ³ . Currently, in the steelworks, such coke oven gas is combined with blast furnace gas, converter gas and purchased fuel gas to meet various demands, but for future gas demands in the steelworks, It is said that it is difficult to deal with this alone, and higher calorie gas is desired.

By the way, against the background of effective utilization of coal resources, a technique of methanizing coke oven gas into higher calorie gas has been proposed (for example, Q. Yuan and BK). Huang, "Production of City Gas by Methanation under Normal Pressure" Proc. Pitts
burg Coal Conf. VOL. 6th, N
o. Vol. 2, pp 721-724, 1989). However, when this methanation technology is carried out, a gas conversion facility such as a methanation reactor is required in addition to a coke oven, which causes a high cost. In addition, according to this methanation technology, the carbon dioxide concentration in the obtained methanation gas becomes extremely high. Therefore, in order to put this into practical use, a separate decarbonation facility is also required.

Further, in the time required from the charging of coal to the coke oven to the end of the carbonization, the high-calorie component gas having a high hydrocarbon content generated within the first 55 to 75% of the time, and the remaining gas A technique for separately recovering a component gas having a high hydrogen content generated within 45 to 25% of the time is disclosed in JP-A-57 / 57.
It is disclosed in Japanese Patent No. 3882. However, in the coke oven, since the carbonization temperature is different near the furnace wall and near the center of the furnace, it is unavoidable that hydrogen is mixed into the hydrocarbon component gas or the hydrocarbon component is mixed into the hydrogen. Cannot get calorie gas or high concentration hydrogen.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to perform thermal decomposition of coal and select a desired component gas of the thermal decomposition gas generated from coal with a relatively simple structure without requiring auxiliary equipment. The present invention is to provide a thermal decomposition device for coal for efficient recovery.

[0008]

Means and Actions for Solving the Problems The present inventors have
In the thermal decomposition process of coal such as steam coal and reformed coal, we focused on the fact that the components of gas generated differ depending on the thermal decomposition temperature.
That is, in general, when coal is thermally decomposed, 350 to 40
At around 0 ° C, coal exhibits thermal softening properties and generates coal tar and gas liquid. In the vicinity of 450 to 500 ° C, the functional groups and side chains in the polymer composing coal are decomposed and solidified while releasing relatively higher hydrocarbons such as ethylene and ethane, methane, carbon monoxide and carbon dioxide. Indicates a contraction phenomenon. When the temperature further rises, a large amount of hydrogen is released due to the decomposition of the peripheral portion of the aromatic condensed ring, and at 700 ° C. or higher, the main component of the thermal decomposition gas becomes hydrogen, and residual carbon is finally produced.

Therefore, if the component gas generated at each thermal decomposition temperature is extracted in the generation temperature region, a desired component gas (for example, high calorie component gas, high concentration hydrogen gas) can be selectively obtained. As a result of further research on this point, the present inventors have used a vertical device as a pyrolyzer of coal from the viewpoint of ease of transfer of coal, so that pyrolysis proceeds as the coal descends inside. A temperature gradient is provided downward from the upper part of the apparatus so that the desired component gas can be selectively recovered from the thermal decomposition area corresponding to the generation temperature of the desired component gas through a recovery means such as a gas recovery pipe. . In addition, a gasification chamber for the thermal decomposition residue of coal was installed at the bottom of the equipment, and the gas generated by gasification was used as a heat source for heating the thermal decomposition area.

That is, according to the present invention, there is provided a coal pyrolysis apparatus for pyrolyzing coal to selectively recover a desired component gas of the pyrolysis gas, which comprises a vertical coal pyrolysis region. Means for heating the pyrolysis region from the upper side to the lower side to a temperature corresponding to the production temperature of each desired component gas with a temperature gradient such that the pyrolysis of coal proceeds, and partitioning into the respective pyrolysis zones And means for recovering each desired component gas in each pyrolysis zone, and means for gasifying the pyrolysis residue of coal and generating a high-temperature gas, provided in the lower part of the pyrolysis region. A vertical coal pyrolysis apparatus is provided, which is characterized in that the hot gas is used for heating the pyrolysis zone.

In the vertical coal pyrolysis apparatus of the present invention, coal descends in the pyrolysis region due to gravity, undergoes pyrolysis in each pyrolysis zone according to its temperature, and produces respective pyrolysis products. . Of these, the desired component gas is selectively recovered from the recovery means. The pyrolysis residue discharged from the pyrolysis region is gasified in the gasification chamber and becomes a high temperature gas, which is used for heating each pyrolysis zone.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic vertical sectional view of a vertical pyrolysis apparatus according to one embodiment of the present invention. As shown in FIG. 1, the present device 10 has a vertically-long hollow rectangular parallelepiped (box-shaped) structure composed of a plate-shaped member 11, and has partition plates 12a and 1 at the center.
A rectangular parallelepiped coal pyrolysis region 13 is defined by 2b. The coal C passes through the hopper 1, the supply damper 2 and the weighing hopper 3 from the upper part of the device, and the thermal decomposition region 13 of the device 10
Supplied within. Coal C is decomposed by gravity into the thermal decomposition area 13
Since it descends inside, no special transfer device is required, and the equipment cost is reduced accordingly.

The space around the coal pyrolysis zone 13 has a heating zone 14 for heating the coal, which descends by gravity in the pyrolysis zone 13 to a predetermined temperature, in order to obtain the desired pyrolysis component gas from the coal. Stipulates. This heating area 14
Is divided into heating chambers 14a to 14d arranged in the vertical direction by plate-shaped members 15a to 15c. Each heating chamber 14
The high temperature gas (gasification gas) generated by gasifying the thermal decomposition residue of coal, which will be described in detail below, is supplied to a to 14d, and the thermal decomposition regions 13 corresponding to the heating chambers 14a to 14d are respectively defined. Heat to the temperature of. By this heating, the thermal decomposition region 13 is divided into the thermal decomposition regions 13a to 13d corresponding to the respective heating temperatures. Pyrolysis area 1
The temperature at which 3a to 13d are heated forms a temperature gradient such that the thermal decomposition of coal proceeds from the upper side to the lower side of the apparatus 10.

Pyrolysis products P1 to P4 (eg P1: coal tar and gas liquids; P2: ethylene and ethane; P3: methane, carbon monoxide and carbon dioxide; P4: hydrogen) from the respective pyrolysis zones 13a to 13d. Etc.), louver-type gas recovery pipes 16a to 16d are vertically provided in the respective thermal decomposition sections 14a to 14d. Since the recovery pipes 16a to 16d are of the louver type, the decomposition products can be efficiently and continuously recovered without being blocked by the coal C descending in the thermal decomposition region 13.

A gasification chamber 20 for gasifying the pyrolysis residue of coal to generate a high-temperature gasification gas is integrally provided below the pyrolysis device 10. Gasification chamber 20
Communicates with the coal thermal decomposition region 13 via a damper 17 for discharging coal thermal decomposition residue from the thermal decomposition device 10.

A gasifying agent generator 30 for generating a gasifying agent for gasifying the thermal decomposition residue of coal is provided outside the apparatus 10. Oxygen, water, and air are supplied to the gasifying agent generator 30 via lines L5 to L7, respectively. The air burns the gasified gas introduced through the line L4. This combustion heat heats oxygen and water (steam). The gasifying agent composed of the mixture of water vapor and oxygen thus generated is line L
It is supplied to the thermal decomposition residue CR in the gasification chamber 20 via 8, L9. The pyrolysis residue CR in the gasification chamber 20 is gasified by the gasifying agent and becomes high-temperature gasification gas, passing through the cyclone 21 from the gas discharge port 20a of the gasification chamber 20,
The heating chambers 14d to 14a are moved in and out through the lines L3 to L1 that connect the gas outlets and inlets of the adjacent heating chambers to each other to heat the thermal decomposition zones 13a to 13b to a predetermined temperature. Thereafter, a part of the gasified gas is discharged to the outside of the system, but as described above, the rest is introduced into the gasifying agent generator 30 through the line L4, burned by air, and burned. After utilizing the heat as a heat source for steaming water and preheating oxygen, the combustion exhaust gas is discharged to the outside of the system through a line L10.

Ash AS which is the gasification residue in the gasification chamber 20
From the ash discharge port 20b through the transfer means 31 to the discharge device 3
2 and then discharged to the container 33.

Now, the gasification gas which is successively generated in the gasification chamber 20 is a high temperature gas of 800 to 900 ° C. By introducing this into each of the heating chambers 14d to 14a in order from the lower side as described above, the temperature of each of the heating chambers 14d to 14a is maintained from the high temperature to the low temperature, and the corresponding thermal decomposition sections 13d to 1
3a is heated to each temperature. For example, the thermal decomposition zones 13a to 13d have a temperature gradient from 250 ° C to 8 ° C.
It is possible to set temperatures up to 00 ° C. More specifically, the thermal decomposition zone 13a is set to 250 to 400 ° C. to recover the coal tar and the gas liquid (P1) from the recovery pipe 16a, and the thermal decomposition zone 13b is set to a temperature of 450 ° C. to remove ethylene and High-calorie component gas (P
2) is recovered from the recovery pipe 16b, and the thermal decomposition area 13c is recovered to 5
A high-calorie component gas (P3) composed of a mixed gas of carbon monoxide and carbon dioxide, whose main component is methane by setting the temperature to 00 ° C., is recovered from the recovery pipe 16c, and the pyrolysis zone 1
By setting 3d to 700 ° C. to 800 ° C., the component gas (P4) containing hydrogen as the main component can be recovered from the recovery pipe 16d.

The moving speed of the coal C in the apparatus 10 is set such that the coal C is in each of the pyrolysis zones 13a to 13d so that the generation of each of the pyrolysis products is sufficiently completed in each of the pyrolysis zones 13a to 13d.
It is desirable that the speed is such that it can stay in 3d.
Such a speed is, for example, by quantitatively controlling the opening and closing of the supply damper 2 and the discharge damper 17 in small quantities of coal in the apparatus 10
It can be achieved by feeding in and / or adjusting the length of the pyrolysis zone 13.

The coal used in the present invention is not particularly limited, and peat, lignite, subbituminous coal, bituminous coal and the like can be used, but lignite and the like having a large amount of volatile matter are used in order to increase the yield of pyrolysis gas. preferable. Moreover, you may use the modified carbon swelled and solidified with tar. In that case, there is an advantage that a large amount of pyrolysis gas can be obtained.

An experimental example in which coal is pyrolyzed by using the pyrolyzer of the present invention and the pyrolyzed component gas is recovered will be described below.

Experimental Example Using the thermal decomposition apparatus 10 shown in FIG.
Is set to 250 to 400 ° C., and the thermal decomposition zone 13b is set to 45
The temperature was set to 0 ° C, the thermal decomposition zone 13c was set to a temperature of 500 ° C, and the thermal decomposition zone 13d was set to a temperature of 700 to 800 ° C.

Optimum charcoal (water content 6.2%, ash content 10.
4%, volatile matter 33.3%, fixed carbon 56.3%) about 3
It was fed into the apparatus 10 at a rate of 0.5 kg / hour.

Pyrolysis zone 1 where coal C is 250-400 ° C
While descending 3a over about 10 hours, coal tar and gas liquid were about 3.00 kg / hr and 3.10 k, respectively.
Recovered at a rate of g / h and then at 450 ° C pyrolysis zone 1
Ethylene content of about 0.2 while descending in 3b over about 3 hours
High calorie gas was recovered, which was composed mainly of 6 kg / hr and about 0.28 kg / hr of ethane. Then, while moving in the pyrolysis zone 13c at 500 ° C. for about 8 hours, methane of about 1.62 kg / hour, carbon monoxide of about 0.30 kg / hour and carbon dioxide of about 0.45 kg / hour were mainly used. The high-calorie gas as a component is recovered, and further, while moving in the thermal decomposition zone 13d at 700 to 800 ° C. for 3 hours, about 0.
A gas containing 11 kg / hour as a main component was recovered. The thermal decomposition residue was introduced into the gasification chamber 20 and gasified with a gasifying agent composed of oxygen and steam to obtain a high temperature gas of 800 to 900 ° C. of about 56.4 kg / hour. Ash content is about 1.4
It was 6 kg / hour. The high-temperature gas generated in the gasification chamber 20 is used to heat the thermal decomposition zones 13d to 13a to the above temperatures, and then a part of the high-temperature gas is used as a fuel gas for heating the gasifying agent generator 30. used. Even if the present apparatus is continuously used for a long time, the coal recovery pipe 16a ...
No occlusion of 16d occurred.

Table 1 below shows some of the results of the above experiments.

[0027]

[Table 1] Table 2 below shows the coke oven gas and the methanated coke oven gas obtained by the “production of city gas by methanation under normal pressure” in comparison with the high-calorie component gas obtained in the above example.

[0028]

[Table 2] As can be seen from the above results, by using the apparatus of the present invention, the desired pyrolysis component gas can be selectively recovered only by the pyrolysis of coal without the need for any additional equipment. The high-calorie gas obtained by the present invention has a high lower heating value (the thermal decomposition zone 13c at 500 ° C).
Lower calorific value of component gas recovered from 7,000 kc
Al / Nm ³ or more, 450 ° C. The lower calorific value of the component gas recovered from the thermal decomposition section 13b is about 13,1.
00 kcal / Nm ³ ) and high-concentration hydrogen gas can be easily obtained. Furthermore, the carbon dioxide concentration in the high-calorie gas is low, and hydrogen gas is not mixed in the high-calorie gas.

[0029]

As described above, according to the present invention, the desired component gas of the pyrolysis gas generated from coal, such as high calorie gas or hydrogen gas, can be efficiently and selectively used without any auxiliary equipment. An apparatus for recovering coal that can be recovered is provided. Since the apparatus of the present invention is of a vertical type, coal moves (descends) in the pyrolysis region by gravity, so that a special apparatus for transferring coal is unnecessary. Further, by recovering the thermal decomposition product from each thermal decomposition area by using the louver type recovery pipe, the thermal decomposition product can be stably and continuously recovered without the recovery pipe being blocked by coal. Furthermore, by making the equipment a narrow box shape, the temperature in the width direction of the pyrolysis area can be made almost uniform, so increasing the length of the pyrolysis area in the vertical direction will increase the scale of the equipment. Can handle. In addition, since the high-temperature gas generated by gasifying the thermal decomposition residue of coal is used as a heat source for heating each thermal decomposition area, operating costs such as fuel costs can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of a vertical coal pyrolyzer of the present invention.

[Explanation of symbols]

2 ... Coal supply damper, 13a-13d ... Pyrolysis area, 1
4a to 14d ... Heating chamber, 16a to 16d ... Louver type pyrolysis product recovery pipe, 20 ... Gasification chamber, 30 ... Gasifying agent generator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Asanuma 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. A coal pyrolysis apparatus for pyrolyzing coal to selectively recover a desired component gas of the pyrolysis gas, comprising a vertical coal pyrolysis region and the pyrolysis region. Means for heating to a temperature corresponding to the production temperature of each desired component gas and partitioning into each thermal decomposition zone with a temperature gradient such that the thermal decomposition of coal proceeds downward from above And a means for recovering each desired component gas, and a means for gasifying the thermal decomposition residue of coal to generate a high temperature gas, which is provided below the thermal decomposition region. Is used for heating the thermal decomposition region.