JPS61179291A - Apparatus for continuous pyrolysis treatment of coal - Google Patents

Abstract

PURPOSE:To remarkably improve the heat transfer from a heat-transfer tube to a coal layer, by blowing a part of a pyrolysis gas from the bottom of a vertical furnace at such a flow rate that a raw material is not fluidized. CONSTITUTION:A vertical furnace 1 is charged with a dried or preheated non- caking bituminous coal or brown coal 10 from a charging port 3 located at the top thereof. The bituminous coal or brown coal 10 is brought into contact with a heat-transfer tube 2 into which a high-temperature gas 11 is continuously fed, causing the bituminous coal or brown coal 10 to be pyrolitically decomposed. The mixture 12 of a pyrolysis gas with a tar is recovered through an extraction port 6 while a high-temperature char 13 is recovered through a discharge port 4 located at the bottom of the furnace 1. The mixture 12 is condensed using a condenser 7 to separate it into a pyrolysis gas 14 and a condensate 15. A part of the gas 14 is returned to the furnace 1 through a blowing port 5 using a blower 8. The sensible head of the high-temperature char is recovered by the gas 14 at the bottom of the furnace 1, and the heat is used for pyrolysis of the coal of the coal layer located at the top of the furnace 1.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a continuous thermal decomposition treatment apparatus for coal.

More specifically, the present invention relates to an apparatus for efficiently producing pyrolysis gas, tar, and char by thermally decomposing non-caking bituminous coal or brown coal with a high volatile content.

Conventional technology Attempts to produce char, which is mainly a solid smokeless fuel, using non-caking bituminous coal or lignite with high volatile content as raw materials have been made.
It has been actively practiced since the early 1990s, and was put into practical use for a time, but it was not established as a permanent industrial technology due to its small scale and economical problems. However, in the 1970s, due to concerns about the amount of coking coal, which is a raw material for metallurgical coke,
No. 02, JP-A-56-136882, JP-A No. 56-136
As seen in Japanese Patent Publication No. 883 and Japanese Patent Publication No. 59-40185, research on char production methods aimed at expanding the variety of coking coal has begun to attract attention.

For example, the invention disclosed in JP-A-56-136882 uses powder in advance.

Crushed highly volatile non-caking coal is dry preheated and then heated to 15°C.
Discloses a method for producing char, which comprises heating to 600° C. or less for decomposition and cooling at a temperature increase rate of less than /min. For example, the device includes a batch-type fluidized bed, a hopper equipped with a device for supplying raw materials to the fluidized bed, and replacing the air inside with an inert gas, and a hopper for the fluidized bed. , and a fluidizing gas supply line for blowing fluidizing gas while changing the flow rate and fluidized bed inlet gas temperature according to the temperature increase pattern.

Furthermore, in the invention disclosed in Japanese Patent Publication No. 59-40185, after drying and heating high volatile content non-slightly caking coal in a preheater, it is charged into an externally heated double rotary kiln having a plurality of heating gas intake ports, and the heated gas is By adjusting the distribution of the amount of heating gas introduced into the intake port, the heating rate of coking coal in the furnace can be adjusted to 5±3℃.
/min, and the temperature is controlled within the range of 450 to 6
A method for pre-treatment of high volatile content non-slightly caking coal is disclosed which comprises cooling after reaching 00°C.

However, these technologies have not yet been established as industrialized technologies, and the reason why coal pyrolysis processing technology with such historical background still cannot be put into practical use as an economical large-scale processing technology is that No rational pyrolysis process has been devised, and no technology has been proposed for processing coal in a state where the three main components (pyrolysis gas, tar, and char) obtained by pyrolysis can be utilized to a high degree. This is thought to be due to the fact that there is no

Therefore, the present inventors investigated a coal pyrolysis treatment apparatus, which is considered a major issue in establishing an industrially advantageous coal pyrolysis treatment technology.

Conventional pyrolysis treatment equipment can be roughly classified into direct heating type and indirect heating type.

First, the direct heating method uses high-temperature gas as a heat source.
A method of thermal decomposition in a fluidized bed or a flying bed, and a method of thermal decomposition by contacting and mixing a solid heat medium (for example, high-temperature alumina balls or high-temperature char) with coal in a rotating drum or mixer are known. However, in the former case, the high-temperature gas that serves as a heat source is mixed with the useful high-calorie gas generated by pyrolysis, which not only increases the amount of gas and makes the gas processing equipment too large, but also increases the calorie content of the mixed gas by pyrolysis. The disadvantage is that the amount of gas produced by the gas is lower than that of the gas generated by the gas, and its utility value is impaired. In addition, although the latter method avoids the loss of calories in the gas generated by pyrolysis, it requires power for circulating and reheating the solid heating medium, and has disadvantages such as the equipment itself becoming oversized. It was not an advantageous method after all.

On the other hand, the indirect heating method uses a bottom-opening horizontal coke oven, a method that heats a rotating drum from the outside, and a method that heats a horizontal cylindrical furnace from the outside while moving the coal inside the cylindrical furnace with a screw conveyor. In addition, as shown in the above-mentioned Japanese Patent Application Laid-Open No. 56-136883, a method has been proposed in which heat exchanger tubes are arranged in a fluidized bed and fluidizing gas is blown from the bottom. However, with the exception of the fluidized bed method, the heat transfer rate is slow and the equipment required is too large compared to the throughput, so it cannot be said to be an economical pyrolysis treatment equipment. However, the disadvantage of having excessive gas processing equipment was unavoidable.

As described above, both the direct heating method and the indirect heating method of coal pyrolysis treatment devices proposed in the past have their own problems, and cannot be said to have been completed as industrialized devices.

SUMMARY OF THE INVENTION An object of the present invention is to solve these drawbacks of the conventional method and provide a coal pyrolysis treatment apparatus that can be put to practical use industrially.

Means for Solving the Problems In order to recover the pyrolysis products produced by the pyrolysis treatment of coal in a highly usable state, the present inventors basically developed a method using a packed bed using an indirect heating method. The present invention was completed based on the discovery that the various drawbacks of the conventional methods described above can be overcome by using a thermal decomposition treatment apparatus.

That is, the coal pyrolysis treatment apparatus of the present invention is an apparatus for pyrolysis treatment of dry or preheated non-caking bituminous coal or lignite into pyrolysis gas, tar and char, and includes a heat exchanger tube for high temperature gas distribution. It has a built-in vertical furnace body, a coal charging port provided at the top of the furnace body, and a discharge port at the bottom,
and an inlet capable of circulating a portion of the pyrolysis gas from the lower part of the furnace body to an extent that the coal does not become fluidized, and an extraction port for the pyrolysis gas and cool provided on the side of the furnace body. It is characterized by having the following.

Here, the extraction port is provided at the top or middle side of the furnace body.

Hereinafter, the coal pyrolysis treatment apparatus of the present invention will be explained in more detail according to a preferred embodiment of the apparatus of the present invention shown in the attached FIG. 1. As is clear from FIG. 1, the apparatus of the present invention includes a vertical furnace body 1, a heat exchanger tube 2 for high-temperature gas distribution built in the furnace body, a charging port 3 in the upper part of the furnace, and a high-temperature char discharged into the lower part. It has an outlet 4 for blowing in the pyrolysis gas from the lower part of the furnace body 1, an inlet 5 for blowing in a part of the pyrolysis gas from the lower part of the furnace body 1, and an inlet 5 provided in the upper or middle part of the furnace body 1 to extract the pyrolysis gas and tar. It mainly consists of an extraction port 6 for

The extraction port 6 communicates with a condenser 7, where the agglomerates are separated and the pyrolysis gas is recovered therefrom. Also,
A portion of the pyrolysis gas is sent via a blower 8 to an inlet 5 at the bottom of the furnace body.

Here, the furnace body 1 may have various shapes, such as a circular cross-sectional structure, a rectangular cross-sectional structure, etc., and is not particularly limited.

Furthermore, another embodiment of the apparatus of the present invention is shown in FIG. In this embodiment, the extraction port 6 for extracting extracted gas is connected to the furnace main body 1.
This is an example provided in the middle of the page. In this embodiment, it is advantageous to provide an inclined plate 9 for adjusting the unloading direction of the coal and to provide space around the extraction port 6 in order to facilitate the extraction of the product gas. Other points are the same as those in FIG. 1, and the same reference numerals as in FIG. 1 are given and explanations are omitted.

In the device of the present invention, the heating high-temperature gas sent into the heat transfer tube 2 is not necessarily limited to an inert gas, since the device of the present invention is of an indirect heating type.
It may be an oxidizing atmospheric gas. Therefore, it is also possible to directly use various combustion waste gases having high sensible heat.

Furthermore, the raw material used in the apparatus of the present invention, that is, "dried or preheated non-caking bituminous coal or lignite" can be prepared by any conventionally known method, such as drying in a hot air drying oven, rapid heating method called Corite method, Any of the methods disclosed in the invention disclosed in No. 59-40185 can be used.

When operating the apparatus of the present invention, first, dry or preheated non-caking raw material, for example lignite 10, is charged into the furnace body 1 from the charging port in the upper part of the furnace, and this is placed inside the furnace body 1. By bringing the gas into contact with the heated heat transfer tube 2, the high temperature gas 11 that is continuously supplied into the tube is thermally decomposed by sensible heat. As a result, the pyrolysis gas and tar mixture (extract) 12 are transferred from the extraction port 6, and the high-temperature char 13 is transferred to the discharge port 4 in the lower part of the furnace.
are collected from each. The extract 12 is then coagulated in a condenser 7 and separated and recovered into a pyrolysis gas 14 and a condensate 15. A part of the recovered pyrolysis gas 14 is reintroduced into the furnace from the inlet 5 using the blower 8, recovers the sensible heat of the high-temperature char in the lower part of the furnace, and causes the thermal decomposition of the coal in the upper packed bed. It can be used for This greatly improves the heat transfer rate, which is a drawback of conventional indirect heating methods. Incidentally, the extracted gas 12 contains tar and water vapor in addition to the pyrolysis gas, and these are removed by the condenser 7°.

In the apparatus of the present invention, the raw material 10 is charged through the charging port 3 in the upper part of the furnace, and after pyrolysis, the high temperature char 13 as a residue is discharged from the discharge port 4 in the lower part of the furnace, using a packed bed heat transfer method. In addition, the amount of pyrolysis gas 14 to be blown from the lower part of the furnace must be such that the raw material 10 is not fluidized. As a result, unlike the fluidized bed heat transfer method, the amount of blown gas is extremely small and large-scale gas treatment equipment is not required, making the apparatus of the present invention an economically extremely advantageous pyrolysis treatment apparatus. You can say that.

Furthermore, as shown in Figure 2, if the gas extraction port is provided in the middle of the furnace, there is no risk that the tar vapor contained in the gas generated by thermal decomposition will be condensed by the low-temperature raw materials in the upper part of the furnace. Therefore, there is an advantage that uniform unloading of raw materials in the furnace can be ensured.

Additionally, since there are no moving parts in the device of the present invention,
The structure of the furnace may be circular or rectangular in cross-section, and has the advantage of being highly flexible in manufacturing the fruiting equipment. It is also possible to downsize the device.

As is clear from the above description, according to the device of the present invention,
It is possible to continuously process a large amount of coal, which was not possible with conventional coal pyrolysis treatment equipment, and it also makes it possible to increase the value of pyrolysis products, making it an excellent choice in the field of coal utilization technology. It can be said that this will greatly contribute to development.

EXAMPLES Below, the advantages of the pyrolysis treatment apparatus of the present invention will be demonstrated through actual operational examples. However, the scope of the invention is not limited by the following examples.

Operation example: Non-caking bituminous coal having the composition and characteristics shown in Table 1 below is dried using a large hot air dryer, and the dry bituminous coal is heated to 130°C to produce the drying process as shown in Figure 1. 50K in a cylindrical coal pyrolysis furnace with an inner diameter of 300 mm and a furnace height of 3 m.
Continuously charged at a feed rate of 82 g/h, 82
Combustion exhaust gas obtained from a hot stove having a temperature of 0° C. was passed through at a flow rate of 85 Nm”/h to cause a thermal decomposition reaction of coal to obtain pyrolysis gas, tar, and char as a residue.

In addition, when a part of the recovered pyrolysis gas is injected from the lower part of the pyrolysis furnace to promote the pyrolysis reaction, the amount of blown gas can be changed to various amounts (1) to change the pyrolysis reaction rate at that flow rate. We investigated the effect on The results are shown in Table 2.

From the results in Table 2, in Test No. 1 (in which no blown gas was used), the thermal decomposition of coal depends on heating only from the heat exchanger tubes, so the exhaust gas temperature at the outlet of the heat exchanger tubes is 53.
The temperature was as high as 6°C, indicating poor heat transfer efficiency. As a result, the temperature of the char was as low as 420°C, and the amount of gas and tar generated was small, indicating that sufficient thermal decomposition was not achieved. On the other hand, when blowing gas is used as in Test Nos. 2.3 and 4, the heat transfer efficiency is greatly improved, the exhaust gas temperature of the heat exchanger tube is greatly reduced, and as a result, the temperature of the char increases and the gas It can be seen that the amount of tar generated increases significantly.

That is, it can be understood that the gas blown from the lower part of the pyrolysis furnace plays the role of effectively imparting the heat of the heat exchanger tubes to the coal as a heat carrier.

However, as seen in Test No. 5, if the blown gas flow rate is too large, part of the coal in the pyrolysis furnace begins to fluidize, and the fine part of the coal is absorbed by the blown gas and pyrolyzed. Although the amount of tar obtained increases as it is entrained in the gas and scattered from the upper part of the furnace, a large amount of coal particles are mixed in as a quinolinous component.
Its commercial value will be extremely low.

In this way, in a device that continuously pyrolyzes coal,
Basically, it takes the form of a pyrolysis furnace with a packed bed using an indirect heating method, and a part of the gas generated by pyrolysis is
By supplying coal from the bottom into the furnace at a flow rate that does not cause coal fluidization, it is possible to significantly improve the heat transfer rate, and also prevent a decrease in the commercial value of the resulting tar. Furthermore, as is clear from this operational example, the pyrolysis gas can be recovered in a high-calorie state.

Effects of the Invention As described in detail above, according to the coal pyrolysis treatment apparatus of the present invention, a part of the gas once decomposed in the pyrolysis furnace is transferred from the lower part of the furnace to an extent that does not cause fluidization of the raw material. Based on the structure that allows injection at a flow rate, the heat transfer coefficient from the heat transfer tubes to the coal seam can be greatly improved, and the sensible heat of the char discharged as residue from the lower part of the furnace can be recovered. death,
The thermal energy can be effectively reused for the thermal decomposition reaction.

As a result, the heat transfer rate can be greatly improved, and the
' The commercial value of the tar as a reaction product is also significantly high.

Such an improvement in the heat transfer rate is extremely advantageous in downsizing the pyrolysis apparatus, and tar and high-calorie pyrolysis gas with few impurities increase their utility value. Therefore, it can be said that the apparatus of the present invention is an unprecedented continuous thermal decomposition treatment apparatus for coal gas.

Furthermore, if the extraction port for the extracted gas as a product is provided in the middle side of the furnace body, the tar vapor contained in the product gas will not be condensed by the low-temperature coal in the upper part of the furnace. It is also possible to achieve the effect of ensuring uniform unloading of coal.

In addition, as a heating gas, oxidizing gas other than inert gas,
For example, combustion waste gas can also be used, so it is economically advantageous.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining a preferable embodiment of the coal pyrolysis treatment apparatus of the present invention.
FIG. 18-2 is a diagram similar to FIG. 1 for explaining another embodiment of the apparatus of the present invention. (Main reference numbers) 1. Furnace body, 2. Heat exchanger tube, 3. Charging port, 4. Discharge port, 5. Inlet port, 6. Extraction port, 7. Condenser, 8.・Blower, 9. Inclined plate, 10. Coal, 11. High temperature gas, 12. Extracted gas. 13... Char, 14... Pyrolysis gas, 15... Condensate Patent applicant: Sumitomo Metal Industries, Ltd. Agent
Patent Attorney Masahiko Arai Figure 1 1: Furnace body 8: Blower 2: Iinukou 111≧ 10: Imi Richness -3
：Upper mounting
13: High + Y 6: 4 origin D14: Chaplet sowing gas Figure 2 1: Lost P main body

Claims (4)

[Claims] (1) An apparatus for thermally decomposing dry or preheated non-caking bituminous coal or lignite into pyrolysis gas, tar, and char, comprising a vertical furnace body with a built-in heat exchanger tube for high-temperature gas distribution; A coal charging port provided at the top of the furnace body and a discharge port at the bottom, and a part of the pyrolysis gas from the bottom of the furnace body,
The coal pyrolysis treatment apparatus is characterized by having an inlet capable of circulating air to an extent that the coal does not become fluidized, and an extraction port for the pyrolysis gas and tar provided on the side of the furnace main body. . (2) The apparatus according to claim 1, wherein the extraction port is provided at an upper part of the furnace body. (3) The apparatus according to claim 1, wherein the extraction port is provided at a middle side of the furnace body. (4) The apparatus according to claim 3, characterized in that an inclined plate is provided around the extraction port of the furnace body to form a space around the extraction port.